Gas barrier layered product and packaging medium, and method for producing gas barrier layered product

ABSTRACT

Provided is a gas barrier layered product including a base material and a layer stacked on at least one surface of the base material, wherein the layer is formed of a composition including: a hydrolyzed and condensed product of at least one compound (L) containing a metal atom to which at least one characteristic group selected from a halogen atom and an alkoxy group has been bonded, wherein the compound (L) contains at least one compound (A) and at least one compound (B), wherein a mole ratio of the compound (A) / the compound (B) is in a range of 0.5/99.5 to 40/60; and a neutralized product of a polymer containing at least one functional group selected from a carboxyl group and a carboxylic anhydride group, wherein at least 55 mol % of a —COO— group contained in the at least one functional group has been neutralized with a metal ion having a valence of two or more. Also provided is a method for producing the gas barrier layered product.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 10/581,448, filed on Jun. 1, 2006, which is a 35 U.S.C. §371National Stage patent application of International patent applicationPCT/JP2004/017874, filed on Dec. 1, 2004, which claims priority toJapanese patent applications JP 2004-235697, filed on Aug. 13, 2004, andJP 2003-403891, filed on Dec. 3, 2003, all of which are incorporatedherein by reference in their entireties.

TECHNICAL FIELD

The present invention relates to a gas barrier layered product and apackaging medium as well as a method for producing a gas barrier layeredproduct.

BACKGROUND ART

Materials for packaging foods and various articles often are required tohave a gas barrier property, particularly, an oxygen barrier property.This is intended to preclude effects such as oxidation degradation ofpackaged contents that is caused due to oxygen, for example.Particularly, with respect to food packages, the presence of oxygenallows microorganisms to proliferate and thereby the contents decays,which is a problem. Hence, in conventional packaging materials, gasbarrier layers that prevent oxygen from permeating therethrough areprovided, so that the permeation of oxygen is prevented, for example.

Such a gas barrier layer can be, for example, a vapor deposition layerof metallic foil, metal, or a metal compound. Generally, aluminum foil,an aluminum vapor deposition layer, a silicon oxide vapor depositionlayer, an aluminum oxide vapor deposition layer, etc. are used. However,metal layers such as the aluminum vapor deposition layer and aluminumfoil have disadvantages in that the packaged contents cannot be seen ordisposability is low, for example. Furthermore, metal compound layerssuch as the silicon oxide vapor deposition layer and the aluminum oxidevapor deposition layer have disadvantages in that the gas barrierproperty thereof is degraded considerably when the packaging material isdeformed, dropped, or subjected to an impact during transportation, forexample.

Moreover, a layer formed of a vinyl-alcohol-based polymer that isexcellent in gas barrier property may be used as a gas barrier layer insome cases. Examples of the vinyl-alcohol-based polymer includepolyvinyl alcohol, an ethylene-vinyl alcohol copolymer, etc. Such alayer formed of a vinyl-alcohol-based polymer has advantages in beingtransparent and having less difficulty in disposal. Accordingly, therange of uses thereof is increasing.

The above-mentioned vinyl-alcohol-based polymer is crystallized throughhydrogen bonds by which hydroxyl groups contained in the moleculesthereof are bonded to each other, and thereby exhibits the gas barrierproperty. Hence, the conventional vinyl-alcohol-based polymer exhibits ahigh gas barrier property in a dry state. However, in a state where ithas absorbed moisture due to, for instance, water vapor, the hydrogenbonds are loosened and thereby the gas barrier property thereof tends todeteriorate. Accordingly, it is difficult to allow a vinyl-alcohol-basedpolymer such as polyvinyl alcohol to exhibit a high level of gas barrierproperty under a high humidity condition.

Moreover, materials containing a polymer compound and a hydrolyzed andcondensed product of metal alkoxide (for instance, tetramethoxysilane)have been studied as materials with a gas barrier property (for example,JP2002-326303A, JP7(1995)-118543A, and JP2000-233478A).

Recently, retort foods are being produced increasingly. The retort foodsare produced by packing contents in a food packaging material and thenimmersing it in hot water to subject it to a sterilization treatment. Insuch a situation, the level of performance that is required of packagingmaterials for retort foods further is increasing. Examples of theperformance include a high bag breaking strength when a food packagingmaterial including contents packed therein is dropped, an oxygen barrierproperty after it is sterilized in hot water, an oxygen barrier propertyunder a high humidity condition until it is delivered to a consumer,etc. Particularly, there is demand for packaging materials that exhibita high oxygen barrier property regardless of humidity, exhibit a highoxygen barrier property even after being subjected to retort processing,and are excellent in strength and transparency. The above-mentionedconventional techniques, however, cannot satisfy such demands well.

DISCLOSURE OF INVENTION

With such a situation in mind, one of the objects of the presentinvention is to provide a gas barrier layered product that exhibits ahigh oxygen barrier property regardless of humidity, exhibits a highoxygen barrier property even after being subjected to retort processing,and is excellent in strength and transparency. Furthermore, anotherobject of the present invention is to provide a method that allows sucha gas barrier layered product to be manufactured industriallyadvantageously.

The present inventors made keen studies assiduously to achieve theabove-mentioned objects. As a result, they found out the following. Thatis, when a layered product including, as a gas barrier layer, a layerformed of a composition that contains: a hydrolyzed and condensedproduct of metal alkoxide; and a polymer containing at least onefunctional group selected from a carboxyl group and a carboxylicanhydride group is immersed in a solution containing a metal ion with avalence of two or more and thereby the above-mentioned functional groupcontained in the polymer is neutralized, the characteristics of thelayer formed of the above-mentioned composition improve dramatically.Then further studies were made. As a result, the present invention wascompleted.

That is, a gas barrier layered product of the present invention includesa base material and a layer stacked on at least one surface of the basematerial. The layer is formed of a composition that includes: ahydrolyzed and condensed product of at least one compound (L) containinga metal atom to which at least one characteristic group selected from ahalogen atom and an alkoxy group has been bonded; and a neutralizedproduct of a polymer containing at least one functional group selectedfrom a carboxyl group and a carboxylic anhydride group. At least a partof the —COO— group contained in the at least one functional group hasbeen neutralized with a metal ion having a valence of two or more.

A packaging medium of the present invention is one in which theabove-mentioned gas barrier layered product of the present invention isused.

Furthermore, a method of the present invention for producing a gasbarrier layered product is characterized by including: a first processof forming a layer made of a composition on a base material; and asecond process of bringing the layer into contact with a solutioncontaining a metal ion with a valence of two or more. The compositionincludes: a hydrolyzed and condensed product of at least one compound(L) containing a metal atom to which at least one characteristic groupselected from a halogen atom and an alkoxy group has been bonded; and apolymer containing at least one functional group selected from acarboxyl group and a carboxylic anhydride group.

The present invention makes it possible to obtain a gas barrier layeredproduct that exhibits a high oxygen barrier property regardless ofhumidity, exhibits a high oxygen barrier property even after beingsubjected to retort processing, and is excellent in strength andtransparency. It is possible for the gas barrier layered product of thepresent invention to have an oxygen transmission rate of 1.0cm³/m²·day·atm or lower in an atmosphere of 20° C. and 85% RH. This gasbarrier layered product can be produced industrially easily by theproduction method of the present invention. The gas barrier layeredproduct is used effectively for packaging materials for foods, medicine,medical equipment, machine parts, and garments, for example. Above all,it is used particularly effectively for food packaging in which a gasbarrier property is required to be obtained under a high humiditycondition.

DESCRIPTION OF THE INVENTION

Embodiments of the present invention are described below. In thefollowing descriptions, specific compounds may be indicated as examplesof the substances that exhibit specific functions. The presentinvention, however, is not limited thereto. Furthermore, materials thatare indicated as examples can be used individually or in combinationunless otherwise specified.

Gas Barrier Layered Product

The gas barrier layered product of the present invention includes a basematerial and a layer stacked on at least one surface of the basematerial. The layer (hereinafter also referred to as a “gas barrierlayer” in some cases) is formed of a composition that includes: ahydrolyzed and condensed product of at least one compound (L) containinga metal atom to which at least one characteristic group (atomic group)selected from a halogen atom and an alkoxy group has been bonded; and aneutralized product of a polymer containing at least one functionalgroup selected from a carboxyl group and a carboxylic anhydride group.At least a part of the —COO— group contained in the at least onefunctional group has been neutralized with a metal ion having a valenceof two or more. In other words, at least a part of the at least onefunctional group and a metal ion with a valence of two or more composesalt.

Hydrolyzed and Condensed Product

For the compound (L), at least one of the compound (A) and/or thecompound (B) that are described below can be used. The compound (A) andthe compound (B) are described as follows.

The compound (A) is at least one compound that is expressed by thefollowing chemical formula (I):M¹(OR¹)_(n)X¹ _(k)Z¹ _(m-n-k)  (I).

In the chemical formula (I), M¹ denotes an atom selected from Si, Al,Ti, Zr, Cu, Ca, Sr, Ba, Zn, B, Ga, Y, Ge, Pb, P, Sb, V, Ta, W, La, andNd. M¹ is preferably Si, Al, Ti, or Zr, particularly preferably Si. Inthe chemical formula (I), R¹ indicates an alkyl group such as a methylgroup, an ethyl group, an n-propyl group, an iso-propyl group, ann-butyl group, a t-butyl group, etc. and is preferably a methyl group oran ethyl group. Furthermore, in the chemical formula (I), X¹ indicates ahalogen atom. Examples of the halogen atom that is indicated by X¹include a chlorine atom, a bromine atom, an iodine atom, etc. but achlorine atom is preferable. In the chemical formula (I), Z¹ denotes analkyl group substituted by a functional group having reactivity to acarboxyl group. In this case, examples of the functional group havingreactivity to a carboxyl group include an epoxy group, an amino group, ahydroxyl group, a halogen atom, a mercapto group, an isocyanate group, aureide group, an oxazoline group, and a carbodiimide group. Among them,an epoxy group, an amino group, an isocyanate group, a ureide group, ora halogen atom is preferable. The functional group is at least oneselected from an epoxy group, an amino group, and an isocyanate group,for example. Examples of the alkyl group that is substituted by such afunctional group can be those described earlier. Moreover, in thechemical formula (I), m is equal to the valence of a metallic elementM¹, while n denotes an integer of 0 to (m−1). Furthermore, in thechemical formula (I), k indicates an integer of 0 to (m−1), and1≦n+k≦(m−1).

Specific examples of the compound (A) includegamma-glycidoxypropyltrimethoxysilane,gamma-glycidoxypropyltriethoxysilane,gamma-glycidoxypropyltrichlorosilane, gamma-aminopropyltrimethoxysilane,gamma-aminopropyltriethoxysilane, gamma-aminopropyltrichlorosilane,gamma-chloropropyltrimethoxysilane, gamma-chloropropyltriethoxysilane,gamma-chloropropyltrichlorosilane, gamma-bromopropyltrimethoxysilane,gamma-bromopropyltriethoxysilane, gamma-bromopropyltrichlorosilane,gamma-mercaptopropyltrimethoxysilane,gamma-mercaptopropyltriethoxysilane,gamma-mercaptopropyltrichlorosilane,gamma-isocyanatopropyltrimethoxysilane,gamma-isocyanatopropyltriethoxysilane,gamma-isocyanatopropyltrichlorosilane,gamma-ureidopropyltrimethoxysilane, gamma-ureidopropyltriethoxysilane,gamma-ureidopropyltrichlorosilane, etc. Preferable examples of thecompound (A) include gamma-glycidoxypropyltrimethoxysilane,gamma-glycidoxypropyltriethoxysilane,gamma-chloropropyltrimethoxysilane, gamma-chloropropyltriethoxysilane,gamma-aminopropyltrimethoxysilane, and gamma-aminopropyltriethoxysilane.

The compound (B) is at least one compound that is expressed by thefollowing chemical formula (II):M²(OR²)_(q)R³ _(p-q-r)X² _(r)  (II).

In the chemical formula (II), M² denotes an atom selected from Si, Al,Ti, Zr, Cu, Ca, Sr, Ba, Zn, B, Ga, Y, Ge, Pb, P, Sb, V, Ta, W, La, andNd. M² is preferably Si, Al, Ti, or Zr, particularly preferably Si, Al,or Ti. In the chemical formula (II), R² indicates an alkyl group such asa methyl group, an ethyl group, an n-propyl group, an iso-propyl group,an n-butyl group, a t-butyl group, etc. and is preferably a methyl groupor an ethyl group. Furthermore, in the chemical formula (II), X² denotesa halogen atom. Examples of the halogen atom that is indicated by X²include a chlorine atom, a bromine atom, an iodine atom, etc. but achlorine atom is preferable. In the chemical formula (II), R³ indicatesan alkyl group, an aralkyl group, an aryl group, or an alkenyl group.Examples of the alkyl group that is indicated by R³ include a methylgroup, an ethyl group, an n-propyl group, an iso-propyl group, ann-butyl group, a t-butyl group, an n-octyl group, etc. Examples of thearalkyl group that is indicated by R³ include a benzyl group, aphenethyl group, a trityl group, etc. Examples of the aryl group that isindicated by R³ include a phenyl group, a naphthyl group, a tolyl group,a xylyl group, a mesityl group, etc. Furthermore, examples of thealkenyl group that is indicated by R³ include a vinyl group, an allylgroup, etc. In the chemical formula (II), p is equal to the valence of ametallic element M², while q denotes an integer of 0 to p. Moreover, inthe chemical formula (II), r indicates an integer of 0 to p, and1≦q+r≦p.

In the chemical formulae (I) and (II), M¹ and M² may be identical toeach other or may be different from each other. In addition, R¹ and R²also may be identical to each other or may be different from each other.

Specific examples of the compound (B) include: silicon alkoxides such astetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane,ethyltrimethoxysilane, octyltrimethoxysilane, phenyltrimethoxysilane,vinyltrimethoxysilane, vinyltriethoxysilane, chlorotrimethoxysilane,chlorotriethoxysilane, dichlorodimethoxysilane, dichlorodiethoxysilane,trichloromethoxysilane, trichloroethoxysilane, etc.; halogenated silanesuch as vinyltrichlorosilane, tetrachlorosilane, tetrabromosilane, etc.;alkoxy titanium compounds such as tetramethoxytitanium,tetraethoxytitanium, tetraisopropoxytitanium,methyltriisopropoxytitanium, etc.; halogenated titanium such astetrachlorotitanium, etc.; alkoxyaluminum compounds such astrimethoxyaluminum, triethoxyaluminum, triisopropoxyaluminum,methyldiisopropoxyaluminum, tributoxyaluminum, diethoxyaluminumchloride, etc.; and alkoxyzirconium compounds such astetraethoxyzirconium, tetraisopropoxyzirconium,methyltriisopropoxyzirconium, etc.

The composition that forms the gas barrier layer of the gas barrierlayered product according to the present invention includes a hydrolyzedand condensed product of the compound (L). At least a part of thehalogen and alkoxy group of the compound (L) is substituted by ahydroxyl group through hydrolysis of the compound (L). Further, acompound to which a metallic element has been bonded via oxygen isformed through condensation of the hydrolysis product. When thiscondensation is repeated, a compound that can be consideredsubstantially as a metal oxide is obtained. In this case, in order tocause the hydrolysis and condensation, it is important that a halogenatom or an alkoxy group has been bonded to metal. When neither a halogenatom nor an alkoxy group has been bonded thereto, hydrolysis andcondensation do not occur or occur very slowly. Accordingly, in such acase, it is difficult to obtain the effect of the present invention.

The hydrolyzed and condensed product of the compound (L) contained inthe gas barrier layer has preferably a condensation degree P, which isdefined below, of 65 to 99%, more preferably 70 to 99%, and furtherpreferably 75 to 99%. The condensation degree P(%) of the hydrolyzed andcondensed product of the compound (L) is calculated as follows.

Suppose the total number of the alkoxy groups and the halogen atomscontained in one molecule of the compound (L) is indicated by a. Whenthe proportion of the compound (L) in which the total number of thecondensed alkoxy groups and halogen atoms in the hydrolyzed andcondensed product of the compound (L) is i is yi(%) of the wholecompound (L), a value of {(i/a)×yi} is calculated with respect to eachproportion yi obtained when i is an integer of 1 to a (including 1 anda). Then the values thus obtained are added. That is, the condensationdegree P(%) is defined by the following mathematical expression:

$\begin{matrix}{P = {\sum\limits_{i = 1}^{a}{\left\{ {\left( {i/a} \right) \times y\; i} \right\}.}}} & \left\lbrack {{Mathematical}\mspace{14mu}{Expression}\mspace{14mu} 1} \right\rbrack\end{matrix}$

With respect to the hydrolyzed and condensed product of the compound (L)contained in the gas barrier layer, the above-mentioned value yi can bedetermined by solid-state NMR (the DD/MAS method), for example.

The hydrolyzed and condensed product can be produced using a rawmaterial by, for example, a technique that is used in a well-knownsol-gel method. Examples of the raw material include the compound (L), apartial hydrolysate of the compound (L), a total hydrolysate of thecompound (L), a partial hydrolyzed and condensed product of the compound(L), a product obtained through condensation of a part of a totalhydrolysate of the compound (L), and a combination thereof These rawmaterials may be produced by a well-known method, or commerciallyavailable raw materials may be used. The raw material is notparticularly limited. For example, a condensate that is obtained throughhydrolysis and condensation of approximately 2 to 10 molecules can beused as the raw material. Specifically, the raw material to be usedherein can be a linear condensate of dimer to decamer obtained throughhydrolysis and condensation of tetramethoxysilane, for example.

The number of molecules to be condensed in the hydrolyzed and condensedproduct of the compound (L) contained in the composition that forms thegas barrier layer, can be controlled through adjustments in the quantityof water, the type and concentration of a catalyst, the temperature atwhich the hydrolysis and condensation are carried out, etc. that areemployed for the hydrolysis and condensation.

The method for producing the hydrolyzed and condensed product of thecompound (L) is not particularly limited. In a typical example of thesol-gel method, hydrolysis and condensation are carried out by addingwater, acid, and alcohol to the above-mentioned raw materials.

In the below, the compound (L) may by described as metal alkoxide (acompound containing metal to which an alkoxy group has been bonded) insome cases. However, a compound containing metal to which halogen hasbeen bonded may be used instead of the metal alkoxide.

As described above, the compound (L) can be at least one of the compound(A) and/or the compound (B). It is preferable that the compound (L)include the compound (A) alone or both the compound (A) and the compound(B), because in this case, the gas barrier layered product has anexcellent gas barrier property. It is further preferable that thecompound (L) be composed substantially of both the compound (A) and thecompound (B) and the mole ratio of the compound (A)/the compound (B) bein the range of 0.5/99.5 to 40/60. When the compound (A) and thecompound (B) are used together in such a ratio, the gas barrier layeredproduct has excellent performance in areas such as a gas barrierproperty, dynamic properties such as a tensile strength and elongation,appearance, and a handling property, for example. The mole ratio of thecompound (A)/the compound (B) is more preferably in the range of 3/97 to40/60, further preferably in the range of 4/96 to 30/70.

In another example of the present invention, an organic group furthermay be bonded to the metal atom of the compound (L). In this case, theorganic group has at least one characteristic group selected from ahalogen atom, a mercapto group, and a hydroxyl group. Hereinafter, thecompound (L) in which such an organic group has been bonded may bereferred to as a “compound (L′)” in some cases. According to thisstructure, a layered product having a particularly good surfaceappearance can be obtained.

The metal atom of the compound (L′) to be used herein can be silicon,tin, and titanium. A silicon atom may be classified into a nonmetallicelement in some cases but is considered as a metal element in thisspecification. Particularly, a silicon atom is preferable since thereaction thereof is easy to control, it allows stable products to beobtained, and it is readily available. An organic group and at least onecharacteristic group selected from a halogen atom and an alkoxy grouphave been bonded to the silicon atom. The organic group has at least onecharacteristic group selected from a halogen atom, a mercapto group, anda hydroxyl group. In addition, another substituent may be bonded to thesilicon atom, as long as the effects of the present invention areobtained. Examples of such a substituent include a hydrogen atom, analkyl group, an alkenyl group, an aryl group, an aralkyl group, and anamino group. Examples of the compound (L′) containing a silicon atominclude compounds that are expressed by the following formula (I′),allyl(chloropropyl)dichlorosilane,bis(chloromethyldimethylsiloxy)benzene,N-(3-triethoxysilylpropyl)gluconamide, andN-(3-triethoxysilylpropyl)-4-hydroxybutyramide.

The compound (L′) may contain at least one compound (A′) that isexpressed by the following chemical formula (I′):Si(OR¹)_(s)R⁴ _(t)X¹ _(u)Z² _(4-s-t-u)  (I′).In the chemical formula (I′), R¹ and R⁴ each denote an alkyl groupindependently; X¹ indicates a halogen atom; Z² denotes an organic grouphaving at least one characteristic group selected from a halogen atom, amercapto group, and a hydroxyl group; s indicates an integer of 0 to 3;t denotes an integer of 0 to 2; u indicates an integer of 0 to 3;1≦s+u≦3; and 1≦s+t+u≦3.

R¹ and R⁴ each are independently an alkyl group such as a methyl group,an ethyl group, an n-propyl group, an iso-propyl group, an n-butylgroup, a t-butyl group, etc. Preferably, R¹ and R⁴ each are a methylgroup or an ethyl group. Examples of the halogen that is indicated by X¹include chlorine, bromine, iodine, etc. The halogen is preferablychlorine.

The organic group Z² may be a hydrocarbon group (with a carbon number ofapproximately one to five) that has been substituted by at least onecharacteristic group selected from a halogen atom, a mercapto group, anisocyanate group, a ureide group, and a hydroxyl group. Examples of suchan organic group include a chloromethyl group, a chloroethyl group, achloropropyl group, a chloroethylmethyl group, or organic groupsobtained by replacing the chloro group thereof by a bromo group, aniodine group, a fluorine group, a mercapto group, or a hydroxyl group.In addition, the organic group Z² may be one having an amide structureand at least one characteristic group selected from a halogen atom, amercapto group, and a hydroxyl group.

Specific examples of the compound (A′) that is expressed by the formula(I′) in which t is 1 or 2 include chloromethyl methyldimethoxysilane,chloromethyl dimethylmethoxysilane, 2-chloroethylmethyl dimethoxysilane,2-chloroethyl dimethylmethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyl dimethylmethoxysilane, mercaptomethylmethyldimethoxysilane, mercaptomethyl dimethylmethoxysilane,2-mercaptoethylmethyl dimethoxysilane, 2-mercaptoethyldimethylmethoxysilane, 3-mercaptopropylmethyl dimethoxysilane,3-mercaptopropyl dimethylmethoxysilane, andbis(chloromethyl)methylchlorosilane. Furthermore, other compounds may beused that are obtained by replacing the methoxy group of theabove-mentioned compounds by a chlorine group or an alkoxy group, suchas an ethoxy group, an n-propoxy group, an iso-propoxy group, ann-butoxy group, t-butoxy group, etc.

Specific examples of the compound (A′) that is expressed by the formula(I′) in which t is 0 include chloromethyltrimethoxysilane,2-chloroethyltrimethoxysilane, 3-chloropropyltrimethoxysilane,2-chloropropyltrimethoxysilane, 4-chlorobutyltrimethoxysilane,5-chloropentyltrimethoxysilane, 6-chlorohexyltrimethoxysilane,(dichloromethyl)dimethoxysilane, (dichloroethyl)dimethoxysilane,(dichloropropyl)dimethoxysilane, (trichloromethyl)methoxysilane,(trichloroethyl)methoxysilane, (trichloropropyl)methoxysilane,mercaptomethyltrimethoxysilane, 2-mercaptoethyltrimethoxysilane,3-mercaptopropyltrimethoxysilane, 2-mercaptopropyltrimethoxysilane,4-mercaptobutyltrimethoxysilane, 5-mercaptopentyltrimethoxysilane,6-mercaptohexyltrimethoxysilane, (dimercaptomethyl)dimethoxysilane,(dimercaptoethyl)dimethoxysilane, (dimercaptopropyl)dimethoxysilane,(trimercaptomethyl)methoxysilane, (trimercaptoethyl)methoxysilane,(trimercaptopropyl)methoxysilane, fluoromethyltrimethoxysilane,2-fluoroethyltrimethoxysilane, 3-fluoropropyltrimethoxysilane,bromomethyltrimethoxysilane, 2-bromoethyltrimethoxysilane,3-bromopropyltrimethoxysilane, iodomethyltrimethoxysilane,2-iodoethyltrimethoxysilane, 3-iodopropyltrimethoxysilane,(chloromethyl)phenyltrimethoxysilane,(chloromethyl)phenylethyltrimethoxysilane,1-chloroethyltrimethoxysilane, 2-(chloromethyl)allyltrimethoxysilane,(3-chlorocyclohexyl)trimethoxysilane,(4-chlorocyclohexyl)trimethoxysilane,(mercaptomethyl)phenyltrimethoxysilane,(mercaptomethyl)phenylethyltrimethoxysilane,1-mercaptoethyltrimethoxysilane,2-(mercaptomethyl)allyltrimethoxysilane,(3-mercaptocyclohexyl)trimethoxysilane,(4-mercaptocyclohexyl)trimethoxysilane,N-(3-triethoxysilylpropyl)gluconamide, andN-(3-triethoxysilylpropyl)-4-hydroxybutylamide. In addition, othercompounds may be used that are obtained by replacing the methoxy groupof the above-mentioned compounds by a chlorine group or an alkoxy group,such as an ethoxy group, an n-propoxy group, an iso-propoxy group, ann-butoxy group, t-butoxy group, etc.

Preferably, the compound (L′) contains at least one compound selectedfrom chloromethyltrimethoxysilane, chloromethyltriethoxysilane,chloromethyltrichlorosilane, 2-chloroethyltrimethoxysilane,2-chloroethyltriethoxysilane, 2-chloroethyltrichlorosilane,3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane,3-chloropropyltrichlorosilane, mercaptomethyltrimethoxysilane,mercaptomethyltriethoxysilane, mercaptomethyltrichlorosilane,2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane,2-mercaptoethyltrichlorosilane, 3-mercaptopropyltrimethoxysilane,3-mercaptopropyltriethoxysilane, 3-mercaptopropyltrichlorosilane,(chloromethyl)phenyltrimethoxysilane,(chloromethyl)phenyltriethoxysilane,(chloromethyl)phenyltrichlorosilane,(chloromethyl)phenylethyltrimethoxysilane,(chloromethyl)phenylethyltriethoxysilane,(chloromethyl)phenylethyltrichlorosilane,(mercaptomethyl)phenyltrimethoxysilane,(mercaptomethyl)phenyltriethoxysilane,(mercaptomethyl)phenyltrichlorosilane,(mercaptomethyl)phenylethyltrimethoxysilane,(mercaptomethyl)phenylethyltriethoxysilane,(mercaptomethyl)phenylethyltrichlorosilane,hydroxymethyltrimethoxysilane, hydroxyethyltrimethoxysilane,hydroxypropyltrimethoxysilane,N-(hydroxyethyl)-N-methylaminopropyltrimethoxysilane,N-(3-triethoxysilylpropyl)gluconamide, andN-(3-triethoxysilylpropyl)-4-hydroxybutylamide.

Among others, it is preferable that the compound (L′) contain at leastone compound selected from chloromethyltrialkoxysilane,chloromethyltrichlorosilane, 2-chloroethyltrialkoxysilane,2-chloroethyltrichlorosilane, 3-chloropropyltrialkoxysilane,3-chloropropyltrichlorosilane, mercaptomethyltrialkoxysilane,mercaptomethyltrichlorosilane, 2-mercaptoethyltrialkoxysilane,2-mercaptoethyltrichlorosilane, 3-mercaptopropyltrialkoxysilane,3-mercaptopropyltrichlorosilane, N-(3-trialkoxysilylpropyl)gluconamide,and N-(3-trialkoxysilylpropyl)-4-hydroxybutylamide. The use of thesecompounds allows a gas barrier layered product with excellenttransparency to be obtained. Particularly preferable compounds (L′)include chloromethyltrimethoxysilane, chloromethyltriethoxysilane,3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane,mercaptomethyltrimethoxysilane, mercaptomethyltriethoxysilane,3-mercaptopropyltrimethoxysilane, and 3-mercaptopropyltriethoxysilane.When these compounds are used as the compound (L′), a gas barrierlayered product that is excellent in both gas barrier property andtransparency can be obtained. The present invention makes it possible toobtain a gas barrier layered product that has a haze value of 3% orlower and therefore has an excellent transparency.

These compounds (L′) may be commercially available compounds or may besynthesized by a well-known method.

The gas barrier layered product produced using the compound (L′) canhave an oxygen transmission rate of 1.0 cm³/m²·day·atm or lower in anatmosphere of 20° C. and 85% RH. In addition, the gas barrier layeredproduct of the example that is described as another example above, canhave a haze value of 3% or lower.

In the example that is described as another example above, the compound(L) further may contain at least one compound (B) that is expressed bythe above-mentioned chemical formula (II) in addition to the compound(A′). In the chemical formulae (I′) and (II), R¹ and R² may be identicalto each other or may be different from each other.

When the compound (L) includes the compound (A′) and the compound (B),the mole ratio of the compound (A′)/the compound (B) is preferably inthe range of 0.1/99.9 to 40/60, more preferably in the range of 0.5/99.5to 30/70, and most preferably in the range of 1/99 to 20/80 (forinstance, 5/95 to 20/80). When the compound (A′) and the compound (B)are used together in such a ratio, a gas barrier layered product isobtained that has excellent performance in areas such as a gas barrierproperty, dynamic properties such as a tensile strength and elongation,appearance, and a handling property, for example.

Carboxylic Acid-Containing Polymer

The composition that forms the gas barrier layer contains a neutralizedproduct of a polymer containing at least one functional group selectedfrom a carboxyl group and a carboxylic anhydride group. In thecomposition, the content of the neutralized product of the polymer isnot particularly limited but can be in the range of 25 wt % to 95 wt %,for example. The neutralized product of the polymer is obtained asfollows: with respect to the polymer (hereinafter also referred to as a“carboxylic acid-containing polymer” in some cases) containing at leastone functional group selected from a carboxyl group and a carboxylicanhydride group, at least a part of the at least one functional groupdescribed above is neutralized with a metal ion having a valence of twoor more. The carboxylic acid-containing polymer has at least twocarboxyl groups or at least one carboxylic anhydride group in onemolecule of the polymer. Specifically, a polymer can be used thatcontains, in one molecule thereof, at least two structure units, each ofwhich has at least one carboxyl group, such as acrylic acid units,methacrylic acid units, maleic acid units, and itaconic acid units. Apolymer also can be used that contains a structure unit having astructure of carboxylic anhydride, such as a maleic anhydride unit and aphthalic anhydride unit. The structure units that have at least onecarboxyl group and/or the structure units that have the structure of acarboxylic anhydride (hereinafter together they may both be describedbriefly as a “carboxylic acid-containing unit (C)” in some cases), whichare contained in the polymer, may be of one type or may be of two typesor more.

When the content of the carboxylic acid-containing unit (C) in all thestructure units of the carboxylic acid-containing polymer is at least 10mol %, a gas barrier layered product can be obtained that has anexcellent gas barrier property under a high humidity condition. Thiscontent is more preferably at least 20 mol %, further preferably atleast 40 mol %, and particularly preferably at least 70 mol %. When thecarboxylic acid-containing polymer includes both the structure unitcontaining at least one carboxyl group and the structure unit having thestructure of carboxylic anhydride, the total of the contents thereofshould be in the above-mentioned range.

Besides the carboxylic acid-containing unit (C), other structure unitsthat can be contained in the carboxylic acid-containing polymer are notparticularly limited. Examples thereof include at least one structureunit selected from: structure units derived from (meth)acrylate esters,such as a methyl acrylate unit, a methyl methacrylate unit, an ethylacrylate unit, an ethyl methacrylate unit, a butyl acrylate unit, abutyl methacrylate unit, etc.; structure units derived from vinylesters, such as a vinyl formate unit, a vinyl acetate unit, etc.; astyrene unit, a p-styrenesulfonic acid unit; and structure units derivedfrom olefins, such as an ethylene unit, a propylene unit, and anisobutylene unit. When the carboxylic acid-containing polymer includesat least two structure units, the carboxylic acid-containing polymer cantake any one of the following forms: the form of an alternatingcopolymer, the form of a random copolymer, the form of a blockcopolymer, and in addition, the form of a tapered copolymer.

Preferable examples of the carboxylic acid-containing polymer includepolyacrylic acid, polymethacrylic acid, and poly(acrylicacid/methacrylic acid). The carboxylic acid-containing polymer may be ofone type or may be a mixture of at least two types of polymers. Forinstance, at least one polymer selected from polyacrylic acid andpolymethacrylic acid may be used. Furthermore, specific examples of thecarboxylic acid-containing polymer that includes the structure unitsdescribed as other structure units above include an ethylene-maleicanhydride copolymer, a styrene-maleic anhydride copolymer, anisobutylene-maleic anhydride alternating copolymer, an ethylene-acrylicacid copolymer, and a saponified product of an ethylene-ethyl acrylatecopolymer.

The molecular weight of the carboxylic acid-containing polymer is notparticularly limited. However, since the gas barrier layered product isto be obtained that has an excellent gas barrier property and excellentdynamic properties such as, for example, drop impact strength, thenumber average molecular weight thereof is preferably at least 5,000,more preferably at least 10,000, and further preferably at least 20,000.There is no particular upper limit on the molecular weight of thecarboxylic acid-containing polymer. Generally, however, it is 1,500,000or less.

Similarly, the molecular weight distribution of the carboxylicacid-containing polymer also is not particularly limited. However, inconsiderations of surface appearance such as haze of the gas barrierlayered product and excellent storage stability of the solution (S) tobe described later, the molecular weight distribution that is indicatedby a ratio of weight average molecular weight/number average molecularweight of the carboxylic acid-containing polymer is preferably in therange of 1 to 6, more preferably in the range of 1 to 5, and furtherpreferably in the range of 1 to 4.

The polymer that forms the gas barrier layer of the gas barrier layeredproduct according to the present invention is obtained by neutralizingat least a part of at least one functional group (hereinafter alsoreferred to as a “functional group (F)” in some cases) selected from acarboxyl group and a carboxylic anhydride group of the carboxylicacid-containing polymer, with a metal ion having a valence of two ormore. In other words, this polymer contains a carboxyl group that hasbeen neutralized with a metal ion having a valence of two or more.

In the polymer that forms the gas barrier layer, for example, at least10 mol % (for instance, at least 15 mol %) of the —COO— groups containedin the functional group (F) have been neutralized with metal ions havinga valence of two or more. The carboxylic anhydride group is consideredto include two —COO— groups. That is, when a mol of carboxyl group and bmol of carboxylic anhydride group exist, the amount of the —COO— groupscontained therein is (a+2b) mol in total. The ratio of the —COO— groupsthat have been neutralized with metal ions having a valence of two ormore to the —COO— groups contained in the functional group (F) ispreferably at least 20 mol %, more preferably at least 30 mol %, furtherpreferably at least 40 mol %, and particularly preferably at least 50mol % (for instance, at least 60 mol %). There is no particular upperlimit on the ratio of the —COO— groups that have been neutralized withmetal ions having a valence of two or more to the —COO— groups containedin the functional group (F). However, the upper limit can be 95 mol % orlower, for example. With the carboxyl group and/or the carboxylicanhydride group of the carboxylic acid-containing polymer beingneutralized with metal ions having a valence of two or more, the gasbarrier layered product of the present invention exhibits an excellentgas barrier property under both a dry condition and a high humiditycondition.

The neutralization degree (the ionization degree) of the functionalgroup (F) can be determined by measuring the infrared absorptionspectrum of the gas barrier layered product by the ATR (attenuated totalreflection) method, or by removing the gas barrier layer from the gasbarrier layered product and then measuring the infrared absorptionspectrum thereof by the KBr method. The peak attributed to C═Ostretching vibration of the carboxyl group or carboxylic anhydride groupobtained before neutralization (before ionization) is observed in therange of 1600 cm⁻¹ to 1850 cm⁻¹. On the other hand, the C═O stretchingvibration of the carboxyl group obtained after the neutralization (theionization) is observed in the range of 1500 cm⁻¹ to 1600 cm⁻¹.Accordingly, they can be evaluated individually with the infraredabsorption spectra thereof. Specifically, the ratio between them isdetermined from the maximum absorbances in the respective ranges, andthen the ionization degree of the polymer that forms the gas barrierlayer of the gas barrier layered product is calculated using ananalytical curve prepared beforehand. The analytical curve can beprepared through the measurements of infrared absorption spectra of aplurality of standard samples that are different in neutralizationdegree from each other.

It is important that the metal ions that neutralize the functional group(F) have a valence of two or more. When the functional group (F) has notbeen neutralized or has been neutralized by only the univalent ions tobe described later, the layered product obtained thereby does not havean excellent gas barrier property. However, when the functional group(F) has been neutralized with a small amount of univalent ions (positiveions) in addition to metal ions with a valence of two or more, the hazeof the gas barrier layered product is reduced and thereby a good surfaceappearance is obtained. Thus, the case where the functional group (F) ofthe carboxylic acid-containing polymer is neutralized with both themetal ions having a valence of two or more and the univalent ions alsois included in the range of the present invention. Examples of the metalions having a valence of two or more include a calcium ion, a magnesiumion, a divalent iron ion, a trivalent iron ion, a zinc ion, a divalentcopper ion, a lead ion, a divalent mercury ion, a barium ion, a nickelion, a zirconium ion, an aluminum ion, a titanium ion, etc. For example,at least one ion selected from a calcium ion, a magnesium ion, a bariumion, and a zinc ion may be used as the metal ion having a valence of twoor more.

In the present invention, it is preferable that 0.1 to 10 mol % of the—COO— groups contained in the functional group (F) (the carboxyl groupand/or the carboxylic anhydride) of the carboxylic acid-containingpolymer have been neutralized with univalent ions. However, when thedegree of the neutralization achieved with the univalent ions is high,the gas barrier property of the gas barrier layered productdeteriorates. The degree of the neutralization of the functional group(F) achieved with the univalent ions is more preferably in the range of0.5 to 5 mol %, further preferably in the range of 0.7 to 3 mol %.Examples of the univalent ions include an ammonium ion, a pyridiniumion, a sodium ion, a potassium ion, a lithium ion, etc. Among them, anammonium ion is preferable.

Inorganic Components and Others

Preferably, the content of inorganic components in the composition thatforms the gas barrier layer is in the range of 5 to 50 wt %, since therange allows the gas barrier layered product to have an excellent gasbarrier property. This content is more preferably in the range of 10 to45 wt %, further preferably in the range of 15 to 40 wt %, and stillfurther preferably in the range of 25 to 40 wt %. The content of theinorganic components in the composition can be calculated from theweight of the raw materials that are used for preparing the composition.That is, suppose the compound (L), a partial hydrolysate of the compound(L), a total hydrolysate of the compound (L), a partial hydrolyzed andcondensed product of the compound (L), a product obtained throughcondensation of a part of a total hydrolysate of the compound (L), or acombination thereof has been totally hydrolyzed and condensed to becomea metal oxide, and then the weight of the metal oxide is calculated. Theweight of the metal oxide thus calculated is considered as the weight ofthe inorganic components contained in the component, and thereby thecontent of the inorganic components is calculated. When an inorganicadditive such as metal salt, a metal complex, a metal oxide, etc. thatare described later is added, the weight of the inorganic additive thathas been added to the composition is added simply to the weight of theinorganic components. The calculation of the weight of the metal oxideis described below further in detail. When the compound (A) that isexpressed by the chemical formula (I) is hydrolyzed and condensedtotally, a compound whose composition is expressed by a formula ofM¹O_((n+k)/2)Z¹ _(m-n-k) is obtained. In this compound, M¹O_((n+k)/2) isa metal oxide. Z¹ is considered not to be included in inorganiccomponents but to be an organic component. On the other hand, when thecompound (B) that is expressed by the chemical formula (II) ishydrolyzed and condensed totally, a compound whose composition isexpressed by a formula of M²O_((q+r)/2)R³ _(p-q-r) is obtained. In thiscompound, M²O_((q+r)/2) is a metal oxide. In this case, the content (%)of the inorganic components is a value obtained by: dividing the weightof the metal oxide by the weight of the components including all thecomponents added by the end of the first process except forvolatilization components, such as solvents and compounds that areproduced in the process in which the above-mentioned compound (L) ischanged into a metal oxide; and then multiplying it by 100.

In the range that does not impair the effects of the present invention,the composition that forms the gas barrier layer may include, ifdesired: inorganic acid metal salt such as carbonate, hydrochloride,nitrate, hydrogen carbonate, sulfate, hydrogen sulfate, phosphate,borate, aluminate, etc.; organic acid-metal salt such as oxalate,acetate, tartrate, stearate, etc.; a metal complex such as anacetylacetonato metal complex like aluminum acetylacetonato, acyclopentadienyl metal complex like titanocene, a cyano metal complex,etc.; a layered clay compound, a crosslinker, polyalcohols, highmolecular compounds other than those, a plasticizer, an antioxidant, anultraviolet absorber, flame retardant, etc. The composition that formsthe gas barrier layer also may include: fine powder of the metal oxideproduced by hydrolyzing and condensing the metal alkoxide by a wetprocess; fine powder of the metal oxide prepared by hydrolyzing,condensing, or burning metal alkoxide by a dry process; or fine silicapowder prepared from water glass, for example.

When polyalcohols are contained in the composition that forms the gasbarrier layer of the gas barrier layered product according to thepresent invention, the gas barrier layered product has a good surfaceappearance. More specifically, when polyalcohols are contained, the gasbarrier layer tends not to be cracked during the production of the gasbarrier layered product and thereby a gas barrier layered product with agood surface appearance is obtained.

Such polyalcohols to be used in the present invention are compounds thathave at least two hydroxyl groups in a molecule, and they includecompounds whose molecular weights range from low to high. Preferably,such polyalcohols are macromolecular compounds such as polyvinylalcohol, partially saponified polyvinyl acetate, an ethylene-vinylalcohol copolymer, polyethylene glycol, polyhydroxyethyl(meth)acrylate,polysaccharide such as starch, and a polysaccharide derivative derivedfrom polysaccharide such as starch, etc.

With respect to the amount of the above-mentioned polyalcohols to beused, the weight ratio of the carboxylic acid-containing polymer/thepolyalcohols is preferably in the range of 10/90 to 99.5/0.5. The weightratio is more preferably in the range of 30/70 to 99/1, furtherpreferably 50/50 to 99/1, and most preferably 70/30 to 98/2.

In the gas barrier layered product of the present invention, a gasbarrier layer that is made of a composition is formed on at least onesurface of the base material. The composition includes a hydrolyzed andcondensed product of the above-mentioned compound (L) and a neutralizedproduct of a carboxyl group-containing polymer. This gas barrier layermay be formed on only one surface of the base material or may be formedon both the surfaces thereof. The layered product in which a gas barrierlayer is formed on both the surfaces of the base material has anadvantage of facilitating a post-processing of attaching another filmthereto, for example.

The thickness of the gas barrier layer is not particularly limited butis preferably in the range of 0.1 μm to 100 μm. When it is thinner than0.1 μm, the gas barrier layered product may have an unsatisfactory gasbarrier property in some cases. On the other hand, when it is thickerthan 100 μm, the gas barrier layer may tend to be cracked while the gasbarrier layered product is processed, transported, and used. Thethickness of the gas barrier layer is more preferably in the range of0.1 μm to 50 μm, further preferably in the range of 0.1 μm to 20 μm.

Base materials formed of various materials can be used as the basematerial of the gas barrier layered product according to the presentinvention. Examples of the base material to be used herein include:films such as a thermoplastic resin film and a thermosetting resin film;fiber aggregates such as fabrics, papers, etc.; wood; and films ofspecified shapes that are formed of a metal oxide, metal, etc. Amongthem, the thermoplastic resin film is particularly useful as a basematerial of the gas barrier layered product that is used for a foodpackaging material. Furthermore, the base material may include a paperlayer. With the use of a base material including a paper layer, alayered product for a paper container is obtained. In addition, the basematerial may have a multilayered structure that is formed of a pluralityof materials.

Examples of the thermoplastic resin film include films obtained throughformation and processing of: polyolefin-based resin such aspolyethylene, polypropylene, etc.; polyester-based resin such aspolyethylene terephthalate, polyethylene-2,6-naphthalate, polybutyleneterephthalate, copolymers thereof, etc.; polyamide-based resin such asnylon 6, nylon 66, nylon 12, etc.; polystyrene, poly(meth)acrylic ester,polyacrylonitrile, polyvinyl acetate, polycarbonate, polyarylate,regenerated cellulose, polyimide, polyetherimide, polysulfone,polyethersulfone, polyetherether ketone, ionomer resins, etc. Preferablebase materials of layered products that are used for food packagingmaterials are films formed of polyethylene, polypropylene, polyethyleneterephthalate, nylon 6, or nylon 66.

The layered product of the present invention further may include anadhesive layer (T) disposed between the base material and the gasbarrier layer. According to this structure, the adhesiveness between thebase material and the gas barrier layer can be improved. The adhesivelayer (T) that is formed of an adhesive resin can be formed by treatingthe surface of the base material with a well-known anchor coating agent,or applying a well-known adhesives onto the surface of the basematerial. As a result of the studies made about various adhesive resins,it was found out that an adhesive resin was preferable that had aurethane bond and contained nitrogen atoms (nitrogen atoms of theurethane bond) whose ratio to the whole resin was in the range of 0.5 to12 wt %. With the use of such an adhesive resin, the adhesivenessbetween the base material and the gas barrier layer particularly can beimproved. When the base material and the gas barrier layer are bondedfirmly to each other with the adhesive layer (T) interposedtherebetween, the gas barrier property and appearance can be preventedfrom deteriorating when the gas barrier layered product of the presentinvention is subjected to processes such as printing, lamination, etc.The content of the nitrogen atoms (nitrogen atoms of the urethane bond)that are contained in the adhesive resin is more preferably in the rangeof 2 to 11 wt %, further preferably in the range of 3 to 8 wt %.

A preferable adhesive resin having a urethane bond is a two-componentreaction type polyurethane-based adhesive in which a polyisocyanatecomponent and a polyol component are mixed together to react with eachother.

The polyisocyanate component to be used herein is one that commonly isused for producing polyurethane, for example, a polyisocyanate monomer,a derivative thereof, etc.

The polyisocyanate monomer to be used herein can be aliphaticdiisocyanate such as hexamethylene diisocyanate, for example. Inaddition, alicyclic diisocyanate such as3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate,dicyclohexylmethane-4,4′-diisocyanate, 1,3- or1,4-bis(isocyanatomethyl)cyclohexane, or a mixture thereof also can beused. Furthermore, aromatic-aliphatic diisocyanate such as 1,3- or1,4-xylylene diisocyanate or a mixture thereof, 1,3- or1,4-bis(1-isocyanato-1-methylethyl)benzene or a mixture thereof, etc.also can be used. Moreover, aromatic diisocyanate such as 2,4- or2,6-tolylenediisocyanate or a mixture thereof, 4,4′-diphenylmethanediisocyanate, p-phenylene diisocyanate, 1,5-naphtylene diisocyanate,etc. also can be used.

For the derivative of the polyisocyanate monomer, polymers ofpolyisocyanate, such as dimers or trimers of the above-mentionedpolyisocyanate monomers can be used. The modified polyisocyanate alsocan be used. Examples thereof include a modified biuret, a modifiedallophanate, or a modified oxadiazinetrion that are obtained through thereactions between the above-mentioned polyisocyanate monomers and water,polyol, or carbon dioxide, respectively. In addition, for instance, apolyol adduct and/or a polyamine adduct are/is used that can be obtainedthrough the reactions between the above-mentioned polyisocyanatemonomers and polyol and/or polyamine, respectively.

These polyisocyanate components may be used individually or two or moreof them may be used together. Preferably, the derivative of apolyisocyanate monomer is used.

Preferably, polyester polyol is used as the above-mentioned polyolcomponent. Polyester polyol contains an ester unit. The ester unit is aunit including an ester bond. It is formed through the reaction betweenpolyol and polybasic acid and/or alkyl ester thereof.

The polybasic acid is not particularly limited. However, preferableexamples of the polybasic acid to be used herein include: aromaticdicarboxylic acid, such as orthophthalic acid, isophthalic acid,terephthalic acid, 2,6-naphthalenedicarboxylic acid, etc., and/or alkylester thereof and dimer acid and aliphatic dicarboxylic acid, such asglutaric acid, succinic acid, adipic acid, pimelic acid, suberic acid,azelaic acid, sebacic acid, dodecanoic diacid, 2-methylsuccinic acid,2-methyladipic acid, 3-methyladipic acid, 3-methylpentanedioic acid,2-methyloctanedioic acid, 3,8-dimethyl decanedioic acid, 3,7-dimethyldecanedioic acid, etc. Furthermore, alkyl ester of the polybasic acid isnot particularly limited. Preferably, however, alkyl esters of theabove-mentioned polybasic acids are used.

Preferable examples of polyol to be used herein include glycols such asethylene glycol, diethylene glycol, propylene glycol, 1,3-butanediol,1,4-butanediol, 2-methyl-1,3-propanediol, neopentyl glycol,1,6-hexanediol, 1,7-heptanediol, 1,9-nonanediol, cyclohexanedimethanol,3-methyl-1,5-pentanediol, 3,3′-dimethylolheptane,2-methyl-1,8-octanediol, etc. Furthermore, triols such as glycerin,trimethylol propane, etc. also can be used preferably. In addition,dimethylol alkanoic acid, such as dimethylol propionic acid, dimethylolbutanoic acid, etc. also can be used preferably.

Polyester polyol is not particularly limited as long as theabove-mentioned polyester unit is contained therein. Polyester polyolcan be synthesized by a well-known method. That is, polyester polyol isobtained by allowing polybasic acid and/or alkyl ester thereof to reactwith polyol in an inert gas atmosphere at 160 to 250° C.

Polyester polyol may be used as a polyol component without furtherprocessing. Furthermore, polyurethane polyester polyol is produced bysubjecting polyester polyol to a chain elongation reaction withpolyisocyanate, which then may be used as a polyol component. Moreover,high-molecular-weight polyester polyol is produced through thecondensation reaction of polyester polyol, which then may be used as apolyol component. When polyester polyol is subjected to the chainelongation reaction or condensation reaction and thereby its molecularweight increases, adhesives with various physical properties can beobtained. When polyester polyol is used as a polyol component withoutfurther processing, the number average molecular weight thereof ispreferably at least 500 but less than 3000, for example.

Preferably, a two-component reaction type polyurethane-based adhesive isapplied to a base material film after an organic solvent is added to thepolyisocyanate component and a polyol component to make an adjustment sothat the concentration of the solid content is in the range of 0.5 to 50wt %. Preferable examples of the organic solvent to be used hereininclude: esters such as methyl acetate, ethyl acetate, etc.; ketonessuch as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone,etc.; and aromatic hydrocarbon such as toluene, xylene, etc. When theseorganic solvents contain a large amount of moisture, the adhesivestrength between the base material and the gas barrier layer that aredisposed with the adhesive layer (T) being interposed therebetweendecreases. The content (a weight ratio) of moisture that is contained inthe organic solvent is preferably 3000 ppm or less, more preferably 2000ppm or less, and further preferably 1000 ppm or less. In order to reducethe amount of moisture that is contained in the organic solvent, it ispreferable that an organic solvent whose initial moisture content islower be used and in addition, operations be carried out in such amanner that the solvent, solution, and gas barrier layer are preventedfrom coming into contact with the air as much as possible. For example,it is preferable to employ methods of, for example, using a device thatis of a closed type and can be operated from the outside, minimizing thenumber of times and the period of time of contact with the air, orsealing an opening with nitrogen.

When the moisture contained in the organic solvent exceeds 3000 ppm, theadhesive layer (T) tends to become inhomogeneous. In order for a basematerial and a gas barrier layer to be bonded firmly to each other withthe adhesive layer (T) being interposed therebetween, it is importantthat the adhesive layer (T) is homogeneous. The inventors found out thatthe homogeneity of the adhesive layer (T) could be evaluated in terms ofvariations in haze value of the gas barrier layered product. The hazevalue is measured by the method described in Examples, and then thestandard deviation is determined. When the value that is three times thestandard deviation is in the range of 0 to 2.0, the above-mentionedadhesiveness is high. This value is more preferably in the range of 0 to1.5, further preferably in the range of 0 to 1.0.

The strength of the gas barrier layered product can be improved byincreasing the thickness of the adhesive layer (T). However, when thethickness is increased excessively, the appearance is deteriorated.Preferably, the thickness of the adhesive layer (T) is in the range of0.04 μm to 0.18 μm. This configuration can prevent the gas barrierproperty and appearance from deteriorating when the gas barrier layeredproduct of the present invention is subjected to processes such asprinting, lamination, etc. In addition, the configuration can improvethe drop strength of the packaging material produced using the gasbarrier layered product of the present invention. The thickness of theadhesive layer (T) is more preferably in the range of 0.06 μm to 0.16μm, further preferably in the range of 0.07 μm to 0.14 μm.

The layered product of the present invention may include a layer of aninorganic substance (hereinafter also referred to as an “inorganiclayer”) between the base material and the gas barrier layer. Theinorganic layer can be formed with an inorganic substance such as aninorganic oxide. The inorganic layer can be formed by a vapor phase filmforming method such as a vapor deposition method.

The inorganic substance that forms the inorganic layer should be onehaving a gas barrier property with respect to oxygen, water vapor, etc.Preferably, it has transparency. The inorganic layer can be formed usinginorganic oxide such as aluminum oxide, silicon oxide, siliconoxynitride, magnesium oxide, tin oxide, or a mixture thereof, forexample. Among them, aluminum oxide, silicon oxide, and magnesium oxidecan be used preferably since they have an excellent barrier propertywith respect to gases such as oxygen, water vapor, etc.

Preferable thickness of the inorganic layer varies depending on the typeof the inorganic oxide that forms the inorganic layer but generally isin the range of 2 nm to 500 nm. The thickness that allows the gasbarrier layered product to have excellent gas barrier property andmechanical property is selected in this range. When the thickness of theinorganic layer is less than 2 nm, the inorganic layer has noreproducibility in exhibiting the barrier property with respect to gasessuch as oxygen and water vapor, and does not exhibit a satisfactory gasbarrier property in some cases. In the case where the thickness of theinorganic layer exceeds 500 nm, the gas barrier property tends todeteriorate when the gas barrier layered product is stretched or bended.Accordingly, the thickness of the inorganic layer is preferably in therange of 5 to 200 nm, more preferably in the range of 10 to 100 nm.

An inorganic layer can be formed by depositing inorganic oxide on a basematerial. Examples of the formation method include a vacuum vapordeposition method, a sputtering method, an ion plating method, achemical vapor deposition method (CVD), etc. Among them, the vacuumvapor deposition method can be used preferably in view of productivity.A preferable heating method that is employed for carrying out the vacuumvapor deposition is one of an electron ray heating method, a resistanceheating method, and an induction heating method. In order to improve theadhesiveness between the inorganic layer and the base material as wellas the denseness of the inorganic layer, the vapor deposition may becarried out using the plasma assist method or the ion beam assistmethod. In order to improve the transparency of the inorganic layer, thereactive vapor deposition method in which, for example, oxygen gas isblown in to cause a reaction may be employed for depositing the layer.

The fine structure of the gas barrier layer is not particularly limited.It, however, is preferable that the gas barrier layer have the finestructure to be described below because in that case, an excellent gasbarrier property can be obtained and the gas barrier property can beprevented from deteriorating when the gas barrier layered product iselongated. A preferable fine structure is a sea-island structure thatconsists of a sea phase (P) and an island phase (Q). The island phase(Q) is a region where the proportion of the hydrolyzed and condensedproduct of the compound (L) is higher as compared to the sea phase (P).

Preferably, the sea phase (P) and the island phase (Q) each have furthera fine structure. For example, the sea phase (P) further may have asea-island structure that consists of a sea phase (P1) that is formedmainly of a neutralized product of a carboxylic acid-containing polymer,and an island phase (P2) that is formed mainly of a hydrolyzed andcondensed product of the compound (L). Furthermore, the island phase (Q)further may have a sea-island structure that consists of a sea phase(Q1) that is formed mainly of a neutralized product of a carboxylicacid-containing polymer, and an island phase (Q2) that is formed mainlyof a hydrolyzed and condensed product of the compound (L). Preferably,the ratio (volume ratio) of [the island phase (Q2)/the sea phase (Q1)]in the island phase (Q) is larger than that of [the island phase(P2)/the sea phase (P1)] in the sea phase (P). The diameter of theisland phase (Q) is preferably in the range of 30 nm to 1200 nm, morepreferably in the range of 50 to 500 nm, and further preferably in therange of 50 nm to 400 nm. The diameters of the island phase (P2) and theisland phase (Q2) are preferably 50 nm or shorter, more preferably 30 nmor shorter, and further preferably 20 nm or shorter.

In order to obtain a structure such as the one mentioned above, suitablehydrolysis condensation of the compound (L) needs to occur prior to thecrosslinking reaction between the compound (L) and a carboxylicacid-containing polymer. It therefore is possible to employ thefollowing methods: using a specific compound (L) together with thecarboxylic acid-containing polymer in a suitable ratio; allowing thecompound (L) to be subjected to hydrolysis condensation before mixing itwith the carboxylic acid-containing polymer; and using a suitablehydrolysis-condensation catalyst, for example.

Besides the base material and the gas barrier layer, the gas barrierlayered product of the present invention also may include another layer(for example, a thermoplastic resin film or paper). With the addition ofsuch another layer, the gas barrier layered product can be provided witha heat-sealing property or can have improved dynamic properties.

Specific examples of the gas barrier layered product of the presentinvention in the case of using a thermoplastic resin film or paper (alayer) for the base material are indicated below. In the followingspecific examples, in order to simplify the description, the word “film(layer)” may be omitted and only materials thereof may be indicated insome cases.

Examples of the structure of the gas barrier layered product accordingto the present invention include: gas barrierlayer/polyester/polyamide/polyolefin, gas barrier layer/polyester/gasbarrier layer/polyamide/polyolefin, polyester/gas barrierlayer/polyamide/polyolefin, gas barrierlayer/polyamide/polyester/polyolefin, gas barrier layer/polyamide/gasbarrier layer/polyester/polyolefin, polyamide/gas barrierlayer/polyester/polyolefin, gas barrierlayer/polyolefin/polyamide/polyolefin, gas barrier layer/polyolefin/gasbarrier layer/polyamide/polyolefin, polyolefin/gas barrierlayer/polyamide/polyolefin, gas barrier layer/polyolefin/polyolefin, gasbarrier layer/polyolefin/gas barrier layer/polyolefin, polyolefin/gasbarrier layer/polyolefin, gas barrier layer/polyester/polyolefin, gasbarrier layer/polyester/gas barrier layer/polyolefin, polyester/gasbarrier layer/polyolefin, gas barrier layer/polyamide/polyolefin, gasbarrier layer/polyamide/gas barrier layer/polyolefin, polyamide/gasbarrier layer/polyolefin, gas barrier/polyester/paper, gas barrierlayer/polyamide/paper, gas barrier layer/polyolefin/paper, polyethylene(PE) layer/paper layer/PE layer/gas barrier layer/polyethyleneterephthalate (PET) layer/PE layer, polyethylene (PE) layer/paperlayer/PE layer/gas barrier layer/polyamide layer/PE layer, PElayer/paper layer/PE layer/gas barrier layer/PE, paper layer/PElayer/gas barrier layer/PET layer/PE layer, PE layer/paper layer/gasbarrier layer/PE layer, paper layer/gas barrier layer/PET layer/PElayer, paper layer/gas barrier layer/PE layer, gas barrier layer/paperlayer/PE layer, gas barrier layer/PET layer/paper layer/PE layer, PElayer/paper layer/PE layer/gas barrier layer/PE layer/hydroxylgroup-containing polymer layer, PE layer/paper layer/PE layer/gasbarrier layer/PE layer/polyamide layer, PE layer/paper layer/PElayer/gas barrier layer/PE layer/polyester layer, etc. From theviewpoints of the heat-sealing property and dynamic property of the gasbarrier layered product, polypropylene or polyethylene is preferable asthe polyolefin, polyethylene terephthalate (PET) is preferable as thepolyester, and nylon 6 is preferable as the polyamide. Furthermore, anethylene-vinyl alcohol copolymer is preferable as the hydroxylgroup-containing polymer. Another layer, for example, a layer of anadhesive or an anchor coat layer may be provided between the respectivelayers, as required.

The packaging medium of the present invention is produced using the gasbarrier layered product of the present invention described above. Thispackaging medium is applicable to various uses. This packaging medium isused preferably for the use where a barrier to gas such as oxygen gas isrequired. For example, the packaging medium of the present invention isused preferably as a packaging medium for a retort food. In addition,when a base material containing a paper layer is used, a paper containercan be obtained.

Method for Producing Gas Barrier Layered Product

Hereinafter, the method for producing a gas barrier layered product ofthe present invention is described. According to this method, the gasbarrier layered product of the present invention can be manufacturedeasily. The materials to be used in the production method of the presentinvention and the structure of the layered product are the same as thosedescribed above. Hence, the same descriptions may not be repeated insome cases.

In the production method of the present invention, first, a layer madeof a composition is formed on a base material (the first process). Thecomposition contains: a hydrolyzed and condensed product of at least onecompound (L) containing a metal atom to which at least onecharacteristic group selected from a halogen atom and an alkoxy grouphas been bonded; and a polymer (a carboxylic acid-containing polymer)containing at least one functional group selected from a carboxyl groupand a carboxylic anhydride group. The first process can be carried out,for example, through: a process of preparing a solution (S) thatincludes a carboxylic acid-containing polymer and at least one compoundcontaining a metallic element selected from the compound (L), a partialhydrolysate of the compound (L), a total hydrolysate of the compound(L), a partial hydrolyzed and condensed product of the compound (L), anda product obtained through condensation of a part of a total hydrolysateof the compound (L); and a process of forming the layer containing theabove-mentioned components by applying the solution (S) to the basematerial and then drying it. The solution (S) can be dried by removingthe solvent contained in the solution (S).

When the carboxylic acid-containing polymer and the compound (L) thathas not been subjected to hydrolysis condensation are mixed together,they may react with each other, which may make it difficult to apply thesolution (S). Hence, it is preferable that the first process include: aprocess of forming a hydrolyzed and condensed product of the compound(L); a process of preparing the solution (S) containing the hydrolyzedand condensed product and a carboxylic acid-containing polymer; and aprocess of forming a gas barrier layer by applying the solution (S) tothe base material and then drying it.

An organic group having at least one characteristic group selected froma halogen atom, a mercapto group, and a hydroxyl group further may bebonded to the metallic atom of the compound (L). That is, the compound(L) may contain the compound (L′) described above. The use of thecompound (L′) makes it possible to obtain a layered product having aparticularly good surface appearance.

In the carboxylic acid-containing polymer that is contained in thesolution (S), as described above, a part (for example, 0.1 to 10 mol %)of the —COO— groups contained in the functional group (F) may have beenneutralized with univalent ions.

Next, the layer formed on the base material is brought into contact witha solution containing metal ions with a valence of two or more (thesecond process; hereinafter this process also may be referred to as an“ionization process” in some cases). At least a part of the functionalgroups (F) (carboxylic acid and/or carboxylic anhydride) contained inthe carboxylic acid-containing polymer in the layer is neutralized withdivalent metal ions through the second process. In this case, theproportion (ionization degree) of the functional groups that areneutralized with the divalent metal ions can be adjusted by changingconditions such as the temperature of the solution containing the metalions, the metal ion concentration, and the period of time of immersingthe layer in the solution containing the metal ions.

The second process can be carried out by spraying the solutioncontaining the metal ions with a valence of two or more on the layerthat has been formed, or immersing both the base material and the layerformed on the base material in the solution containing the metal ionswith a valence of two or more, for example.

In the below, the layered product obtained before the ionization processmay be referred to as a “layered product (A)” while the layered productobtained after the ionization process may be referred to as a “layeredproduct (B)” in some cases.

Hereinafter, the at least one compound containing a metallic elementselected from the compound (L), a partial hydrolysate of the compound(L), a total hydrolysate of the compound (L), a partial hydrolyzed andcondensed product of the compound (L), and a product obtained throughcondensation of a part of a total hydrolysate of the compound (L) may bereferred to as a “compound (L) component”. The solution (S) can beprepared using the compound (L) component, a carboxylic acid-containingpolymer, and a solvent. For example, a method (1) can be employed inwhich the compound (L) component is added to a solvent in which acarboxylic-acid containing polymer has been dissolved, which then ismixed together. Furthermore, a method (2) also can be employed in whicha compound (A) that is a compound (L) component is added to a solvent inwhich a carboxylic-acid containing polymer has been dissolved, andthereafter the compound (L) component is added thereto, which then ismixed together. Moreover, a method (3) also is employed in which anoligomer (one type of hydrolyzed and condensed product) is prepared fromthe compound (L) component in the presence of a solvent or in theabsence of a solvent, and then a solution in which a carboxylic-acidcontaining polymer has been dissolved is mixed with the oligomer. Thecompound (L) component and the oligomer thereof may be added to asolvent individually or may be added to a solvent in the form of asolution in which they have been dissolved.

By using the above-mentioned preparation method (3) as a method ofpreparing the solution (S), a gas barrier layered product is obtainedthat has a particularly high gas barrier property. Hereinafter, thepreparation method (3) is described further in detail.

The preparation method (3) includes: a process (St1) of preparing asolution by dissolving a carboxylic acid-containing polymer in asolvent; a process (St2) of preparing an oligomer by hydrolyzing andcondensing the compound (L) component under specific conditions; and aprocess (St3) of mixing the solution obtained in the process (St1) andthe oligomer obtained in the process (St2) together.

The solvent that is used for dissolving the carboxylic acid-containingpolymer in the process (St1) can be selected according to the type ofthe carboxylic acid-containing polymer. For example, in the case of awater-soluble polymer such as polyacrylic acid and polymethacrylic acid,water is preferable. In the case of polymers such as anisobutylene-maleic anhydride copolymer and a styrene-maleic anhydridecopolymer, water containing an alkaline material such as ammonia, sodiumhydroxide, or potassium hydroxide is preferable. Moreover, in theprocess (St1), it is possible to use the following material together, aslong as it does not hinder the carboxylic acid-containing polymer fromdissolving: alcohols such as methanol, ethanol, etc.; ethers such astetrahydrofuran, dioxane, trioxane, etc.; ketones such as acetone,methyl ethyl ketone, etc.; glycols such as ethylene glycols, propyleneglycol, etc.; glycol derivatives such as methyl cellosolve, ethylcellosolve, n-butyl cellosolve, etc.; glycerin; acetonitrile,dimethylformamide, dimethylsulfoxide, sulfolane, dimethoxyethane, etc.

In the process (St2), it is preferable that the oligomer is obtained byhydrolyzing and condensing the compound (L) component in a reactionsystem that includes the compound (L) component, an acid catalyst,water, and, if necessary, an organic solvent. Specifically, thetechnique that is used in a well-known sol-gel method is applicable.When the compound (L) is used as the compound (L) component, a gasbarrier layered product with a further improved gas barrier property canbe obtained.

The acid catalyst that is used in the process (St2) can be a well-knownacid catalyst. Examples thereof include hydrochloric acid, sulfuricacid, nitric acid, p-toluenesulfonic acid, benzoic acid, acetic acid,lactic acid, butanoic acid, carbonic acid, oxalic acid, maleic acid,etc. Among them, hydrochloric acid, sulfuric acid, nitric acid, aceticacid, lactic acid, and butanoic acid are particularly preferable. Apreferable amount of the acid catalyst to be used varies depending onthe type of the catalyst to be used. However, with respect to 1 mol ofmetal atoms of the compound (L) component, the amount of the acidcatalyst is preferably in the range of 1×10⁻⁵ to 10 mol, more preferablyin the range of 1×10⁻⁴ to 5 mol, and further preferably in the range of5×10⁻⁴ to 1 mol. When the amount of the acid catalyst to be used is inthis range, a gas barrier layered product with an excellent gas barrierproperty is obtained.

A preferable amount of water to be used in the process (St2) variesdepending on the type of the compound (L) component. However, withrespect to 1 mol of the alkoxy group or the halogen atoms (when the bothare present together, 1 mol in total) of the compound (L) component, theamount of water to be used is preferably in the range of 0.05 to 10 mol,more preferably in the range of 0.1 to 4 mol, and further preferably inthe range of 0.2 to 3 mol. When the amount of water to be used is inthis range, a gas barrier layered product to be obtained has aparticularly excellent gas barrier property. In the process (St2), whenusing a component containing water like hydrochloric acid, it ispreferable that the amount of water to be used be determined inconsideration of the quantity of water to be introduced by thecomponent.

Furthermore, in the reaction system of the process (St2), an organicsolvent may be used if needed. The organic solvent to be used is notparticularly limited, as long as the compound (L) component is dissolvedtherein. For example, alcohols, such as methanol, ethanol, isopropanol,normal propanol, etc. can be used suitably as the organic solvent.Alcohol having a molecular structure (an alkoxy component) of the sametype as that of the alkoxy group that is contained in the compound (L)component is used further suitably. Specifically, methanol is preferablewith respect to tetramethoxysilane, while ethanol is preferable withrespect to tetraethoxysilane. The amount of the organic solvent to beused is not particularly limited. Preferably, however, it allows theconcentration of the compound (L) component to be 1 to 90 wt %, morepreferably 10 to 80 wt %, and further preferably 10 to 60 wt %.

In the process (St2), the temperature of the reaction system that isemployed when the compound (L) component is hydrolyzed and condensed inthe reaction system is not necessarily limited. However, the temperatureof the reaction system is generally in the range of 2 to 100° C.,preferably in the range of 4 to 60° C., and more preferably in the rangeof 6 to 50° C. The reaction time varies depending on the reactionconditions such as the quantity and type of the catalyst. It, however,is generally in the range of 0.01 to 60 hours, preferably in the rangeof 0.1 to 12 hours, and more preferably in the range of 0.1 to 6 hours.The atmosphere of the reaction system also is not necessarily limited.The atmosphere to be employed herein can be an air atmosphere, a carbondioxide atmosphere, an argon atmosphere, or a nitrogen gas streamatmosphere.

In the process (St2), all amount of the compound (L) component may beadded to the reaction system at once, or the compound (L) component maybe added to the reaction system little by little over time. In both thecases, it is preferable that the total amount of the compound (L)component to be used satisfy the above-mentioned suitable range. Whenthe oligomer that is prepared in the process (St2) is indicated in termsof the above-mentioned condensation degree P, it is preferable that ithave a condensation degree of approximately 25 to 60%.

In the process (St3), the solution (S) is prepared by mixing theoligomer that is derived from the compound (L) component and a solutionincluding a carboxylic acid-containing polymer together. From theviewpoints of the preservation stability of the solution (S) and the gasbarrier property of the gas barrier layered product to be obtained, thepH of the solution (S) is preferably in the range of 1.0 to 7.0, morepreferably in the range of 1.0 to 6.0, and further preferably in therange of 1.5 to 4.0.

The pH of the solution (S) can be adjusted by a well-known method. Forexample, it can be adjusted by adding: an acid compound such ashydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, aceticacid, butanoic acid, ammonium sulfate, etc.; and a basic compound suchas sodium hydroxide, potassium hydroxide, ammonia, trimethylamine,pyridine, sodium carbonate, sodium acetate, etc. In this case, whenusing a basic compound that introduces univalent positive ions into thesolution, an effect can be obtained that a part of the carboxyl groupand/or carboxylic anhydride group of the carboxylic acid-containingpolymer can be neutralized by the univalent ions.

The state of the solution (S) that is prepared in the process (St3)changes with the passage of time and finally the solution (S) becomes agel composition. The period of time required for the solution (S) tobecome a gel state depends on the composition of the solution (S). Inorder to apply the solution (S) steadily to a base material, it ispreferable that the solution (S) be one whose viscosity is stable over along period of time and then increases gradually. Preferably, thecomposition of the solution (S) is adjusted so that its viscositymeasured with a Brookfield viscometer (a B-type viscosity meter: 60 rpm)is 1 N·s/m² or lower (more preferably 0.5 N·s/m² or lower, andparticularly preferably 0.2 N·s/m² or lower) even after the solution (S)is allowed to stand still at 25° C. for two days, with the time when allthe amount of compound (L) component has been added being taken as areference point. Furthermore, it is more preferable that the compositionof the solution (S) be adjusted so that its viscosity is 1 N s/m² orlower (more preferably 0.1 N·s/m² or lower, and particularly preferably0.05 N·s/m² or lower) even after the solution (S) is allowed to standstill at 25° C. for ten days. Further preferably, the composition of thesolution (S) is adjusted so that its viscosity is 1 N·s/m² or lower(more preferably 0.1 N·s/m² or lower, and particularly preferably 0.05N·s/m² or lower) even after the solution (S) is allowed to stand stillat 50° C. for ten days. When the viscosity of the solution (S) is in theabove-mentioned ranges, the solution (S) is excellent in storagestability and the gas barrier layered product to be obtained has animproved gas barrier property in many cases.

In order to adjust the composition so that the viscosity of the solution(S) is in the above-mentioned ranges, the methods that can be employedherein are, for example, adjusting the concentration of the solidcontent, adjusting the pH, and adding a viscosity modifier such ascarboxymethyl cellulose, starch, bentonite, tragacanth gum, stearate,alginate, methanol, ethanol, n-propanol, isopropanol, etc.

In order to facilitate the application of the solution (S) to the basematerial, an organic solvent that can be mixed with the solution (S)uniformly may be added to the solution (S) in the range in which thestability of the solution (S) is not impaired. Examples of the organicsolvent that can be added include: lower alcohols such as methanol,ethanol, n-propanol, isopropanol, etc.; ethers such as tetrahydrofuran,dioxane, trioxane, etc.; ketones such as acetone, methyl ethyl ketone,methyl vinyl ketone, methyl isopropyl ketone, etc.; glycols such asethylene glycol, propylene glycol, etc.; glycol derivatives such asmethyl cellosolve, ethyl cellosolve, n-butyl cellosolve, etc.; glycerin;acetonitrile, dimethylformamide, dimethylacetamide, dimethylsulfoxide,sulfolane, dimethoxyethane, etc.

In the range in which the effects of the present invention are notimpaired, the solution (S) also may include, if desired: inorganicacid-metal salt such as carbonate, hydrochloride, nitrate, hydrogencarbonate, sulfate, hydrogen sulfate, phosphate, borate, aluminate,etc.; organic acid-metal salt such as oxalate, acetate, tartrate,stearate, etc.; a metal complex such as an acetylacetonato metal complexlike aluminum acetylacetonato, a cyclopentadienyl metal complex liketitanocene, a cyano metal complex, etc.; a layered clay compound, acrosslinker, the above-mentioned polyalcohols, high molecular compoundsother than those, a plasticizer, an antioxidant, an ultravioletabsorber, flame retardant, etc. The solution (S) also may include finepowder of the metal oxide produced by hydrolyzing and condensing theabove-mentioned metal alkoxide by a wet process; fine powder of themetal oxide produced by hydrolyzing, condensing, or burning metalalkoxide by a dry process; or fine silica powder prepared from waterglass, for example.

With respect to the amount of polyalcohols to be added to the solution(S), the weight ratio of the carboxylic acid-containing polymer/thepolyalcohols is preferably in the range of 10/90 to 99.5/0.5. The weightratio is more preferably in the range of 30/70 to 99/1, furtherpreferably 50/50 to 99/1, and most preferably 70/30 to 98/2.

The solution (S) prepared in the process (St3) is applied to at leastone surface of the base material. Before the application of the solution(S), the surface of the base material may be treated with a well-knownanchor coating agent, or a well-known adhesive may be applied to thesurface of the base material. The method of applying the solution (S) tothe base material is not particularly limited and a well-known methodtherefore can be employed. Preferable examples of the method include acast method, a dipping method, a roll coating method, a gravure coatingmethod, a screen printing method, a reverse coating method, a spraycoating method, a kit coating method, a die coating method, a meteringbar coating method, a chamber doctor coating method, a curtain coatingmethod, etc.

After the application of the solution (S) to the base material, thesolvent contained in the solution (S) is removed and thereby a layeredproduct (a layered product (A)) in the state before being subjected tothe ionization process is obtained. The method of removing the solventis not particularly limited and a well-known method therefore can beused. Specifically, methods such as a hot-air drying method, a hot rollcontact method, an infrared heating method, a microwave heating method,etc. can be used individually or in combination. The drying temperatureis not particularly limited as long as it is lower than the flow starttemperature of the base material by at least 15 to 20° C. and also islower than the thermal decomposition start temperature of the carboxylicacid-containing polymer by at least 15 to 20° C. The drying temperatureis preferably in the range of 80° C. to 200° C., more preferably in therange of 100 to 180° C., and further preferably in the range of 110 to180° C. The solvent can be removed under either a normal pressure or areduced pressure.

The layered product (A) obtained through the above-mentioned process isbrought into contact with a solution (hereinafter also referred to as a“solution (MI) in some cases) containing metal ions with a valence oftwo or more (ionization process). Thus, the gas barrier layered productof the present invention is obtained. The ionization process may becarried out in any stage, as long as the effects of the presentinvention are not impaired. The ionization process can be carried outbefore or after the layered product is processed into the form of apackaging material, or after the packaging material is filled withcontents and then is sealed, for example.

The solution (MI) can be prepared by dissolving, in a solvent, acompound (a polyvalent metal compound) that releases the metal ions witha valence of two or more upon dissolution. The solvent to be used forpreparing the solution (MI) is desirably water but may be a mixture ofwater and an organic solvent that can be mixed with water. Examples ofsuch a solvent include organic solvents of: lower alcohols such asmethanol, ethanol, n-propanol, isopropanol, etc.; ethers such astetrahydrofuran, dioxane, trioxane, etc.; ketones such as acetone,methyl ethyl ketone, methyl vinyl ketone, methyl isopropyl ketone, etc.;glycols such as ethylene glycol, propylene glycol, etc.; glycolderivatives such as methyl cellosolve, ethyl cellosolve, n-butylcellosolve, etc.; glycerin; acetonitrile, dimethylformamide,dimethylacetamide, dimethylsulfoxide, sulfolane, dimethoxyethane, etc.

The polyvalent metal compound to be used herein can be a compound thatreleases metal ions (i.e. metal ions with a valence of two or more)described as examples with respect to the gas barrier layered product ofthe present invention. Examples thereof include: calcium acetate,calcium hydroxide, barium hydroxide, calcium chloride, calcium nitrate,calcium carbonate, magnesium acetate, magnesium hydroxide, magnesiumchloride, magnesium carbonate, iron(II) acetate, iron(II) chloride,iron(III) acetate, iron(III) chloride, zinc acetate, zinc chloride,copper(II) acetate, copper(III) acetate, lead acetate, mercury(II)acetate, barium acetate, zirconium acetate, barium chloride, bariumsulfate, nickel sulfate, lead sulfate, zirconium chloride, zirconiumnitrate, aluminum sulfate, potassium alum (KAl (SO₄)₂), titanium(IV)sulfate, etc. Only one of the polyvalent metal compounds may be used ortwo or more of them may be used in combination. Preferable examples ofthe polyvalent metal compound include calcium acetate, calciumhydroxide, magnesium acetate, zinc acetate, and barium acetate. Thesepolyvalent metal compounds may be used in the form of a hydrate.

The concentration of the polyvalent metal compound in the solution (MI)is not particularly limited. It, however, is preferably in the range of5×10⁻⁴ wt % to 50 wt %, more preferably in the range of 1×10⁻² wt % to30 wt %, and further preferably in the range of 1 wt % to 20 wt %.

When the layered product (A) is brought into contact with the solution(MI), the temperature of the solution (MI) is not particularly limited.However, the higher the temperature, the higher the ionization rate ofthe carboxyl group-containing polymer. Preferable temperature is, forexample, in the range of 30 to 140° C. The temperature is preferably inthe range of 40° C. to 120° C., more preferably in the range of 50° C.to 100° C.

Desirably, after the layered product (A) is brought into contact withthe solution (MI), the solvent that has remained on the layered productis removed. The method of removing the solvent is not particularlylimited. A well-known method can be used. Specifically, dryingtechniques such as a hot-air drying method, a hot roll contact method,an infrared heating method, a microwave heating method, etc. can be usedindividually or two or more of them can be used in combination. Thetemperature at which the solvent is removed is not particularly limitedas long as it is lower than the flow start temperature of the basematerial by at least 15 to 20° C. and also is lower than the thermaldecomposition start temperature of the carboxylic acid-containingpolymer by at least 15 to 20° C. The drying temperature is preferably inthe range of 40° C. to 200° C., more preferably in the range of 40 to150° C., and further preferably in the range of 40 to 100° C. Thesolvent can be removed under either a normal pressure or a reducedpressure.

In order not to impair the appearance of the surface of the gas barrierlayered product, it is preferable that the superfluous polyvalent metalcompound that has adhered to the surface of the layered product beremoved before or after the solvent is removed. A preferable method ofremoving the polyvalent metal compound is washing using a solvent inwhich the polyvalent metal compound dissolves. A solvent that can beused for the solution (MI) can be employed as the solvent in which thepolyvalent metal compound dissolves. It is preferable that the samesolvent as that of the solution (MI) be used.

The production method of the present invention further may include aprocess of heat-treating the layer formed in the first process at atemperature of 120 to 240° C., after the first process and before and/orafter the second process. In other words, the layered product (A) or (B)may be heat-treated. The heat treatment can be carried out at any stageafter the solvent of the solution (S) that had been applied has beenremoved substantially. However, when the layered product (i.e. thelayered product (A)) is heat-treated before being subjected to theionization process, a gas barrier layered product with a good surfaceappearance is obtained. The temperature that is employed for the heattreatment is preferably in the range of 120° C. to 240° C., morepreferably in the range of 130° C. to 230° C., and further preferably inthe range of 150° C. to 210° C. The heat treatment can be carried out inair, a nitrogen atmosphere, an argon atmosphere, etc.

In the production method of the present invention, the layered product(A) or (B) may be irradiated with ultraviolet rays. The ultravioletirradiation may be carried out anytime after the solvent of the solution(S) that had been applied has been removed substantially. The method ofthe ultraviolet irradiation is not particularly limited. A well-knowmethod can be used herein. The wavelengths of the ultraviolet rays thatare used for the irradiation are preferably in the range of 170 to 250nm, more preferably in the range of 170 to 190 nm and/or in the range of230 to 250 nm. Furthermore, instead of the ultraviolet irradiation,irradiation may be carried out with radial rays such as electron rays,gamma rays, etc.

Only either of the heat treatment and the ultraviolet irradiation may becarried out, or the both may be employed together. When the heattreatment and/or the ultraviolet irradiation are/is carried out, thelayered product may exhibit a further improved gas barrier property insome cases.

When the surface of the base material is subjected to a treatment (atreatment to be carried out using an anchor coating agent, orapplication of an adhesive) before the application of the solution (S)in order to dispose the adhesive layer (T) between the base material andthe gas barrier layer, it is preferable that a maturing process in whichthe base material to which the solution (S) has been applied is allowedto stand at a relatively lower temperature for a long period of time becarried out after the first process (the application of the solution(S)) but before the above-mentioned heat treatment and the secondprocess (the ionization process). The temperature that is employed forthe maturing process is preferably 30 to 200° C., more preferably 30 to150° C., and further preferably 30 to 120° C. The period of time forwhich the maturing process is carried out is preferably in the range of0.5 to 10 days, more preferably in the range of 1 to 7 days, and furtherpreferably 1 to 5 days. When such a maturing process is carried out, theadhesiveness between the base material and the gas barrier layer furtherimproves. It is preferable that the above-mentioned heat treatment (theheat treatment at 120° C. to 240° C.) further be carried out after thismaturing process.

The gas barrier layered product of the present invention has anexcellent barrier property with respect to gases such as oxygen, watervapor, carbon dioxide, nitrogen, etc. It can maintain an excellentbarrier property to a greater extent even under a high humiditycondition or after it is subjected to a bending condition. In addition,even after it is subjected to retort processing, it exhibits anexcellent gas barrier property. Thus, the gas barrier layered product ofthe present invention has a good gas barrier property that does notdepend on the environmental conditions such as humidity, and it exhibitsan excellent gas barrier property even after it is subjected to bendingconditions. It therefore is applicable to various uses. For instance,the gas barrier layered product of the present invention is particularlyuseful as a food packaging material (particularly a packaging materialfor retort foods). The gas barrier layered product of the presentinvention also can be used as a material for packaging chemicals such asagricultural chemicals and medicines, industrial materials such asprecision materials, garments, etc.

EXAMPLES

Hereinafter, the present invention is described further in detail usingexamples. The present invention, however, is not limited by theexamples.

The measurements and evaluations that were carried out in the followingexamples were performed by the following methods (1) to (8). Some of theabbreviations that are used in the following description aboutmeasurement methods and evaluation methods may be described later. Themeasurement results and evaluation results are indicated in the tablesthat appear after the descriptions of the examples and comparativeexamples.

(1) Storage Stability Examples 1 to 21 and Comparative Examples 1 to 3

After the solution (S) to be used for forming a gas barrier layer wasprepared (in the examples of the present invention, after the additionof the compound (L) component to an aqueous solution of polyacrylic acidhad been completed), it was allowed to stand still at 25° C. for twodays. The viscosity of this solution was measured using the Brookfieldviscometer (a B-type viscometer, the revolution speed: 60 rpm) beforeand after it was allowed to stand. The rate of increase in viscosity wascalculated from the initial viscosity and that obtained after two days.The method of determining the storage stability of the solution (S) ofExamples 23 to 28 is described in Example 23.

(2) Oxygen Barrier Property

With respect to the layered product having a specified structure, theoxygen transmission rate was measured using an oxygen transmission ratetest system (“MOCON OX-TRAN 10/50”, manufactured by Modern Controls,Inc.). Specifically, the layered product was set in such a manner thatthe gas barrier layer faced the oxygen supply side and OPET (in anexample 11, the other gas barrier layer) faced the career gas side. Thenthe oxygen transmission rate (unit: cm³/m²·day·atm) was measured underconditions including a temperature of 20° C., an oxygen pressure of 1atm, and a career gas pressure of 1 atm. For the measurement, threehumidity conditions, specifically, 65% RH, 85% RH, and 95% RH, wereemployed. The oxygen supply side and the career gas side had the samehumidity. In Examples 23 to 28, the measurement was carried out with thehumidity set at 85% RH.

(3) Oxygen Barrier Property after Retort Processing

Two layered products (with a size of 12 cm×12 cm) having a specifiedstructure were produced. Then the two layered products were stackedtogether in such a manner that their gas barrier layers faced theoutside. Thereafter, three sides of the layered products wereheat-sealed by 5 mm from the edges thereof. Distilled water 80 g waspoured between the two layered products that had been heat-sealed andthen the remaining fourth side was heat-sealed in the same manner. Thus,a pouch containing the distilled water therein was produced.

Subsequently, the pouch was immersed in tap water or ion-exchanged waterthat filled an autoclave, and thereby retort processing was carried outat 120° C. for 30 minutes. After the retort processing, heating wasstopped. At the time when the inner temperature decreased to 60° C., thepouch was removed from the autoclave. Thereafter, the pouch was allowedto stand for one hour in a room having a temperature of 20° C. and ahumidity adjusted to 85% RH. Then, the portion that had been heat-sealedwas cut off with scissors, and water that had adhered to the surfaces ofthe gas barrier layered products was wiped off by lightly pressing apaper towel against the surfaces. Thereafter, the pouch was allowed tostand for one week in a room having a temperature of 20° C. and ahumidity adjusted to 85% RH. Then the oxygen transmission rate of thelayered product thus obtained was measured and thereby the oxygenbarrier property after the retort processing was evaluated.

The oxygen transmission rate was measured using the oxygen transmissionrate test system (“MOCON OX-TRAN 10/50”, manufactured by ModernControls, Inc.). Specifically, the layered product was set in such amanner that a gas barrier layer faced the oxygen supply side and PPfaced the career gas side. Then, the oxygen transmission rate (unit:cm³/m²·day·atm) was measured under conditions including a temperature of20° C., a relative humidity on the oxygen supply side of 85%, a relativehumidity on the carrier gas side of 100%, an oxygen pressure of 1 atm,and a career gas pressure of 1 atm. The concentration of the calciummetal contained in the tap water used for the retort processing was 15ppm. Furthermore, the absence of metal atoms in the ion-exchanged waterwas confirmed. In the following examples and comparative examples, theretort processing was carried out using tap water unless otherwisespecified. The concentration of calcium contained in the tap water usedin the retort processing was 15 ppm

(4) Tensile Strength and Elongation

A sample with a size of 1.5 cm×1.5 cm was cut out of the layered productproduced for evaluating the above-mentioned item, (2) Oxygen BarrierProperty. With respect to the sample, its tensile strength andelongation were measured by a method that was in conformity with JISK7127.

(5) Dropped Bag Breaking Strength

Using the pouch that was produced for evaluating the above-mentioneditem, (3) Oxygen Barrier Property after Retort Processing, the droppedbag breaking strength was determined. That is, a pouch was subjected tothe same retort processing as that carried out for the evaluation in theabove-mentioned item (3). Thereafter, the pouch was removed from theautoclave and then was allowed to stand for one hour in a room having atemperature of 20° C. and a humidity adjusted to 85% RH. This pouch waslifted to a height of 1.5 m in such a manner as to be in parallel withthe floor surface and then was dropped. The pouch was dropped repeatedlyuntil it was broken to allow water to leak from the inside. Thus, thenumber of times it was dropped before the water leaked was determined.With respect to one type of layered product, ten pouches were prepared.The average of the numbers of times the ten pouches were dropped wastaken as a value of the dropped bag breaking strength.

(6) Surface Appearance Examples 1 to 22 and Comparative Examples 1 to 3

With respect to the layered product produced for evaluating theabove-mentioned item, (2) Oxygen Barrier Property, its transparency andsurface condition such as irregularities of the gas barrier layer wereobserved visually. Then the case where it was transparent and thesurface was smooth was judged as “excellent (AA)”, the case where it wasslightly hazy but had no problem practically and a good surfacecondition was judged as “good (A)”, and the case where it was nottransparent or the surface condition was not good due to, for example,irregularities caused at the surface was judged as “poor (B)”.

(7) Neutralization Degree (Ionization Degree) of Carboxyl Group withMetal Ions

With respect to the layered product produced for evaluating theabove-mentioned item, (2) Oxygen Barrier Property and the layeredproduct obtained after the retort processing that was produced forevaluating the item, (3) Oxygen Barrier Property after RetortProcessing, the peak of the stretching vibration of C═O that wascontained in the gas barrier layer was observed in the mode of ATR(attenuated total reflection) using a Fourier Transform InfraredSpectrophotometer (manufactured by Shimadzu Corporation; 8200PC). Thepeak that was derived from the stretching vibration of C═O of thecarboxyl group contained in the carboxylic acid-containing polymerbefore ionization was observed in the range of 1600 cm⁻¹ to 1850 cm⁻¹.The stretching vibration of C═O of the carboxyl group after ionizationwas observed in the range of 1500 cm⁻¹ to 1600 cm⁻¹. Then, the ratiothereof was calculated from the maximum absorbances in the respectiveranges. Subsequently, the ionization degree was determined using theratio and the analytical curve that was prepared beforehand by thefollowing method.

[Preparation of Analytical Curve]

Polyacrylic acid with a number average molecular weight of 150,000 wasdissolved in distilled water, and carboxyl groups were neutralized witha predetermined amount of sodium hydroxide. A base material was coatedwith an aqueous solution of the neutralized product of the polyacrylicacid thus obtained, in such a manner that the aqueous solution had thesame thickness as that of the gas barrier layer of the layered productto be subjected to the measurement of ionization degree. This then wasdried. The base material used herein was a drawn PET film (manufacturedby Toray Industries, Inc.; Lumirror (Trade Name); Thickness: 12 μm;hereinafter abbreviated as “OPET” in some cases) whose surface wascoated with a two-component anchor coating agent (manufactured by MitsuiTakeda Chemicals, Inc.; Takelac 3210 (Trade Name) and Takenate A3072(Trade Name); hereinafter abbreviated as “AC” in some cases). Thus, 11standard samples of layered products (each of which had a structure of alayer formed of a neutralized product of polyacrylic acid/AC/OPET) wereproduced. The 11 standard samples were different from each other inneutralization degree of the carboxyl groups, with the neutralizationdegree varying between 0 and 100 mol % by increments of 10 mol %. Withrespect to these samples, the infrared absorption spectrum was measuredin the mode of ATR (attenuated total reflection) using a FourierTransform Infrared Spectrophotometer (manufactured by ShimadzuCorporation; 8200PC). With respect to the two peaks corresponding to thestretching vibration of C═O that was contained in the layer formed ofthe neutralized product of polyacrylic acid, i.e. the peak observed inthe range of 1600 cm⁻¹ to 1850 cm⁻¹ and the peak observed in the rangeof 1500 cm⁻¹ to 1600 cm⁻¹, the ratio between the maximum absorbances wascalculated. Then using the ratios thus calculated and the ionizationdegrees of the respective standard samples, the analytical curve wasprepared.

(8) Content of Inorganic Component

The content of the inorganic components of the gas barrier layerobtained before the ionization treatment was calculated by the methoddescribed above, i.e., the method of calculating it from the weight ofthe raw materials.

(9) Evaluation of Change in Appearance through Heating (Examples 14 to21 and Comparative Example 3)

A layered product with a size of 10 cm×10 cm was produced. Then the foursides of the layered product were fixed to a wooden frame using aheat-resisting tape. The layered product fixed to the wooden frame wasin a stretched state and was not loose. The layered product stuck on thewooden frame was allowed to stand still in a hot air drier whoseinternal temperature was 120° C., for five minutes. Subsequently, thelayered product stuck on the wooden frame was taken out of the dryer andthen was allowed to stand to cool in a room temperature atmosphere forten minutes. Thereafter, the appearance of the layered product wasobserved. The appearance was evaluated in accordance with the followingreferences:

-   AA: No change in appearance as compared to that observed before the    layered product was placed in the hot air dryer;-   A: Poor appearance was evident in few portions; and-   B: Poor appearance was evident partially or throughout.

(10) Measurement of Peel Strength

The layered product having a structure of PET layer/AC layer/barrierlayer/adhesive layer (1)/nylon layer/adhesive layer (2)/polypropylenelayer was produced. This layered product was cut so as to have a widthof 15 mm. T-type peel strength was measured at a tensile rate of 250mm/min, with the separation plane being between the barrier layer andthe adhesive layer (1).

(11) Measurement of Haze Value Examples 14 to 21 and Comparative Example3

A layered product with a size of 10 cm×10 cm was produced. With respectto the layered product, nine points were selected evenly and haze valuesthereof were measured. Equipment used for measuring haze values wasHR-100 manufactured by Murakami Color Research Laboratory Co., Ltd. TheHaze values were measured according to the specified measuring method(ASTM D1003-61). Then standard deviation was calculated from themeasured values obtained at the nine points.

(12) Observation of Fine Structure of Gas Barrier Layer

A section of a layered product was coated with epoxy resin and a verythin section was produced using a device (Reichert ULTRACUT-S)manufactured by Leica. Then the section was observed using atransmission electron microscope (H-800NA) manufactured by Hitachi, Ltd.

(13) Storage Stability Examples 23 to 28

After the solution (S) to be used for forming a gas barrier layer wasprepared, specifically, after the addition of the compound (L) componentto the aqueous solution of polyacrylic acid was completed, it wasallowed to stand still at 25° C. Then the number of days that had passeduntil this solution stopped flowing completely was counted.

(14) Surface Appearance Examples 23 to 28

With respect to the layered product produced for evaluating theabove-mentioned item, (2) Oxygen Barrier Property, its haze value wasmeasured according to the method of JIS K 7105 using a haze meter(HR-100; Murakami Color Research Laboratory, Inc.).

The haze value [(diffused light transmittance/total lighttransmittance)×100] is used as a typical index for evaluating thetransparency of a material. Generally, it can be said that the lower thehaze value, the higher the transparency of the material. The level ofthe haze value below which the material is considered to besatisfactorily transparent cannot simply be decided because the criteriafor judgment thereof vary depending on uses. However, when the hazevalue is 3% or lower, the material can be used suitably even for useswhere considerably high transparency is required.

Example 1

Polyacrylic acid (PAA) with a number average molecular weight of 150,000was dissolved in distilled water. Thereafter, ammonia water was addedthereto and thereby 1.5 mol % of the carboxyl groups of the polyacrylicacid were neutralized. Thus, a polyacrylic acid aqueous solution wasobtained, in which the solid content concentration was 10 wt %.

Next, 68.4 parts by weight of tetramethoxysilane (TMOS) was dissolved in82.0 parts by weight of methanol. Subsequently, 13.6 parts by weight ofgamma-glycidoxypropyltrimethoxysilane was dissolved therein. Thereafter,5.13 parts by weight of distilled water and 12.7 parts by weight of 0.1N(0.1 normal) hydrochloric acid were added thereto. Thus, a sol wasprepared. This was allowed to undergo hydrolysis and condensationreactions at 10° C. for one hour while being stirred. The sol thusobtained was diluted with 185 parts by weight of distilled water, whichthen was added promptly to 634 parts by weight of the above-mentioned10-wt % polyacrylic acid aqueous solution that was being stirred. Thus asolution (S1) was obtained. With respect to this solution (S1), thestorage stability was evaluated by the method described above.

On the other hand, a drawn PET film (OPET; Lumirror (Trade Name),manufactured by Toray Industries, Inc.) was coated with a two-componentanchor coating agent (AC; Takelac 3210 (Trade Name) and Takenate A3072(Trade Name), manufactured by Mitsui Takeda Chemicals, Inc.), which thenwas dried. Thus a base material (AC/OPET) having an anchor coat layerwas produced. The anchor coat layer of the base material was coated withthe solution (S1) using a bar coater in such a manner that the solution(S1) formed a layer with a thickness of 2 μm after being dried. This wasdried at 80° C. for five minutes and then was subjected to a maturingprocess at 50° C. for three days (72 hours). Furthermore, this then washeat-treated in dry air at 200° C. for five minutes. Thus, a layeredproduct (the gas barrier layer (2 μm)/AC/OPET (12 μm)) with a gasbarrier layer that was transparent and colorless and had a goodappearance was obtained (hereinafter, this layered product may bereferred to as a “layered product (1)”).

Next, calcium acetate was dissolved in distilled water in such a manneras to have a concentration of 10 wt %. This aqueous solution was keptwarm at 80° C. Then, the layered product (1) obtained above was immersedin this aqueous solution (80° C.; MI-1) for approximately 20 seconds.Thereafter, this layered product was removed therefrom. Then thesurfaces of the layered product were washed with distilled water whosetemperature had been adjusted to 80° C. After that, it was dried at 80°C. for five minutes. Thus, a layered product (B-1) of the presentinvention was obtained. With respect to the layered product (B-1), theneutralization degree of the carboxyl groups of the polyacrylic acidcontained in the gas barrier layer was determined by the aforementionedmethod. As a result, it was proved that 60 mol % of the carboxyl groupshad been neutralized by calcium ions. With respect to the layeredproduct (B-1) obtained in the above-mentioned manner, the oxygen barrierproperty, surface appearance, tensile strength and elongation, andcontent of inorganic components were evaluated by the aforementionedmethods.

A sample with a size of 10 cm×10 cm was cut from the layered product(B-1), and the haze value thereof was measured by the aforementionedmethod. The value that was three times the standard deviation of thehaze value was 0.20, which was considered to be an excellent value.Furthermore, the fine structure of the gas barrier layer was observedwith a transmission electron microscope. The gas barrier layer had asea-island structure that consisted of a sea phase (P) and an islandphase (Q). The island phase (Q) had an ellipse shape, and the diameterof the ellipse was 50 to 500 nm in the major axis direction.

The sea phase (P) had a sea-island structure that consisted of a seaphase (P1) and an island phase (P2). The sea phase (P1) was formedmainly of the neutralized product of polyacrylic acid, while the islandphase (P2) was formed mainly of the hydrolyzed and condensed product oftetramethoxysilane. The diameter of the island phase (P2) wasapproximately 20 nm or shorter.

The island phase (Q) had a sea-island structure that consisted of a seaphase (Q1) and an island phase (Q2). The sea phase (Q1) was formedmainly of the neutralized product of polyacrylic acid, while the islandphase (Q2) was formed mainly of the hydrolyzed and condensed product oftetramethoxysilane. The diameter of the island phase (Q2) wasapproximately 20 nm or shorter. Judging from the picture obtained withthe electron microscope, the sea phase (P) and the island phase (Q) wereformed of the same components, but the island phase (Q) had a higherconcentration of hydrolyzed and condensed product of tetramethoxysilane.

Furthermore, an drawn nylon film (Emblem (Trade Name), manufactured byUnitika, Ltd.; with a thickness of 15 μm; hereinafter may be abbreviatedas “ONy” in some cases) and a polypropylene film (RXC-18 (Trade Name),manufactured by Tohcello Co., Ltd.; with a thickness of 50 μm;hereinafter may be abbreviate as “PP” in some cases) each were coatedwith a two-component adhesive (A-385 (Trade Name) and A-50 (Trade Name),manufactured by Mitsui Takeda Chemicals, Inc.), which then were dried.Then the films thus obtained were laminated with the above-mentionedlayered product (B-1; gas barrier layer/AC/OPET). Thus, a layeredproduct (B-1-1) that had a structure of gas barrierlayer/AC/OPET/adhesive/ONy/adhesive/PP was obtained. With respect tothis layered product, the dropped bag breaking strength, ionizationdegree after the retort processing, and oxygen transmission rate afterthe retort processing were measured. The ionization degree after theretort processing was 92 mol %, while the oxygen transmission rate afterthe retort processing was lower than 0.2 cm³/m²·day·atm. Thus, withrespect to the both, the layered product exhibited excellent values.

Example 2

First, the layered product (1) described in Example 1 was produced. Onthe other hand, magnesium acetate was dissolved in distilled water insuch a manner as to have a concentration of 10 wt %. Thus, an aqueoussolution was prepared, and it was kept warm at 80° C. The layeredproduct (1) was immersed in this aqueous solution (80° C.; MI-2) forapproximately 20 seconds. Thereafter, this layered product was removedtherefrom. Then the surfaces of the layered product were washed withdistilled water whose temperature had been adjusted to 80° C. Afterthat, it was dried at 80° C. for five minutes. Thus, a layered product(B-2) of the present invention was obtained. With respect to the layeredproduct (B-2), the neutralization degree of the carboxyl groups of thepolyacrylic acid contained in the gas barrier layer was determined bythe aforementioned method. As a result, it was proved that 64 mol % ofthe carboxyl groups had been neutralized by magnesium ions. In addition,with respect to the layered product (B-2), the oxygen barrier property,surface appearance, tensile strength and elongation, and content ofinorganic components were evaluated by the aforementioned methods.

Furthermore, using the layered product (B-2), a layered product (B-2-1)that had a structure of gas barrierlayer/AC/OPET/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 1. With respect to this layered product, the dropped bagbreaking strength, ionization degree after the retort processing, andoxygen transmission rate after the retort processing were measured. Theionization degree after the retort processing was 88 mol %, while theoxygen transmission rate after the retort processing was lower than 0.2cm³/m²·day·atm. Thus, with respect to the both, the layered productexhibited excellent values.

Example 3

First, the layered product (1) described in Example 1 was produced. Onthe other hand, zinc acetate was dissolved in distilled water in such amanner as to have a concentration of 10 wt %. Thus, an aqueous solutionwas prepared, and it was kept warm at 80° C. The layered product (1) wasimmersed in this aqueous solution (80° C.; MI-3) for approximately 20seconds. Thereafter, this layered product was removed therefrom. Thenthe surfaces of the layered product were washed with distilled waterwhose temperature had been adjusted to 80° C. After that, it was driedat 80° C. for five minutes. Thus, a layered product (B-3) of the presentinvention was obtained. With respect to the layered product (B-3), theneutralization degree of the carboxyl groups of the polyacrylic acidcontained in the gas barrier layer was determined by the aforementionedmethod. As a result, it was proved that 60 mol % of the carboxyl groupshad been neutralized by zinc ions. In addition, with respect to thelayered product (B-3), the oxygen barrier property, surface appearance,tensile strength and elongation, and content of inorganic componentswere evaluated by the aforementioned methods.

Furthermore, using the layered product (B-3), a layered product (B-3-1)that had a structure of gas barrierlayer/AC/OPET/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 1. With respect to this layered product, the dropped bagbreaking strength, ionization degree after the retort processing, andoxygen transmission rate after the retort processing were measured. Theionization degree after the retort processing was 90 mol %, while theoxygen transmission rate after the retort processing was lower than 0.2cm³/m²·day·atm. Thus, with respect to the both, the layered productexhibited excellent values.

Example 4

Polyacrylic acid (PAA) with a number average molecular weight of 150,000was dissolved in distilled water, and thereby a polyacrylic acid aqueoussolution was obtained, in which the solid content concentration was 10wt %.

Next, 68.4 parts by weight of tetramethoxysilane (TMOS) was dissolved in82.0 parts by weight of methanol. Subsequently, 13.6 parts by weight ofgamma-glycidoxypropyltrimethoxysilane was dissolved therein. Thereafter,5.13 parts by weight of distilled water and 12.7 parts by weight of 0.1Nhydrochloric acid were added thereto. Thus, a sol was prepared. This wasallowed to undergo hydrolysis and condensation reactions at 10° C. forone hour while being stirred. The sol thus obtained was diluted with 185parts by weight of distilled water, which then was added promptly to 634parts by weight of the above-mentioned 10-wt % polyacrylic acid aqueoussolution that was being stirred. Thus a solution (S4) was obtained. Withrespect to this solution (S4), the storage stability was evaluated bythe method described above.

Next, a layered product (4) that had a structure of gas barrier layer (2μm)/AC/OPET (12 μm) was produced by the same method as in Example 1except that the solution (S4) was used instead of the solution (S1). Thegas barrier layer of the layered product (4) was transparent andcolorless and had a good surface appearance.

Next, the layered product (4) was subjected to the ionization treatmentusing the calcium acetate aqueous solution (MI-1) under the sameconditions as those employed in Example 1. Subsequently, superfluouscalcium acetate was washed away with distilled water whose temperaturehad been adjusted to 80° C. Thereafter, it was dried at 80° C. for fiveminutes. Thus, a layered product (B-4) of the present invention wasobtained. With respect to the layered product (B-4), the neutralizationdegree of the carboxyl groups of the polyacrylic acid contained in thegas barrier layer was determined by the aforementioned method. As aresult, it was proved that 63 mol % of the carboxyl groups had beenneutralized by calcium ions. With respect to the layered product (B-4),the oxygen barrier property, surface appearance, tensile strength andelongation, and content of inorganic components were evaluated by theaforementioned methods.

Furthermore, using the layered product (B-4), a layered product (B-4-1)that had a structure of gas barrierlayer/AC/OPET/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 1. With respect to this layered product, the dropped bagbreaking strength, ionization degree after the retort processing, andoxygen transmission rate after the retort processing were measured. Theionization degree after the retort processing was 92 mol %, while theoxygen transmission rate after the retort processing was lower than 0.2cm³/m²·day·atm. Thus, with respect to the both, the layered productexhibited excellent values.

Example 5

Polyacrylic acid (PAA) with a number average molecular weight of 150,000was dissolved in distilled water, and thereby a polyacrylic acid aqueoussolution was obtained, in which the solid content concentration was 10wt %.

Next, 60.8 parts by weight of tetramethoxysilane (TMOS) was dissolved in88.0 parts by weight of methanol. Subsequently, 27.2 parts by weight ofgamma-glycidoxypropyltrimethoxysilane was dissolved therein. Thereafter,5.20 parts by weight of distilled water and 12.9 parts by weight of 0.1Nhydrochloric acid were added thereto. Thus, a sol was prepared. This wasallowed to undergo hydrolysis and condensation reactions at 10° C. forone hour while being stirred. The sol thus obtained was diluted with 239parts by weight of distilled water, which then was added promptly to 567parts by weight of the above-mentioned 10-wt % polyacrylic acid aqueoussolution that was being stirred. Thus a solution (S5) was obtained. Withrespect to this solution (S5), the storage stability was evaluated bythe method described above.

Next, a layered product (5) that had a structure of gas barrier layer (2μm)/AC/OPET (12 μm) was produced by the same method as in Example 1except that the solution (S5) was used instead of the solution (S1). Thegas barrier layer of the layered product (5) was transparent andcolorless and had a good surface appearance.

Next, the layered product (5) was subjected to the ionization treatmentusing the calcium acetate aqueous solution (MI-1) under the sameconditions as those employed in Example 1. Subsequently, superfluouscalcium acetate was washed away with distilled water whose temperaturehad been adjusted to 80° C. Thereafter, it was dried at 80° C. for fiveminutes. Thus, a layered product (B-5) of the present invention wasobtained. With respect to the layered product (B-5), the neutralizationdegree of the carboxyl groups of the polyacrylic acid contained in thegas barrier layer was determined by the aforementioned method. As aresult, it was proved that 55 mol % of the carboxyl groups had beenneutralized by calcium ions. With respect to the layered product (B-5),the oxygen barrier property, surface appearance, tensile strength andelongation, and content of inorganic components were evaluated by theaforementioned methods.

Furthermore, using the layered product (B-5), a layered product (B-5-1)that had a structure of gas barrierlayer/AC/OPET/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 1. With respect to this layered product, the dropped bagbreaking strength, ionization degree after the retort processing, andoxygen transmission rate after the retort processing were measured. Theionization degree after the retort processing was 87 mol %, while theoxygen transmission rate after the retort processing was lower than 0.2cm³/m²·day·atm. Thus, with respect to the both, the layered productexhibited excellent values.

Example 6

Polyacrylic acid (PAA) with a number average molecular weight of 150,000was dissolved in distilled water, and thereby a polyacrylic acid aqueoussolution was obtained, in which the solid content concentration was 10wt %.

Next, 36.3 parts by weight of gamma-glycidoxypropyltrimethoxysilane wasdissolved in 36.3 parts by weight of methanol. Thereafter, 1.55 parts byweight of distilled water and 3.84 parts by weight of 0.1N hydrochloricacid were added thereto. Thus, a sol was prepared. This was allowed toundergo hydrolysis and condensation reactions at 10° C. for one hourwhile being stirred. The sol thus obtained was diluted with 179 parts byweight of distilled water, which then was added promptly to 743 parts byweight of the above-mentioned 10-wt % polyacrylic acid aqueous solutionthat was being stirred. Thus a solution (S6) was obtained. With respectto this solution (S6), the storage stability was evaluated by the methoddescribed above.

Next, a layered product (6) that had a structure of gas barrier layer (2μm)/AC/OPET (12 μm) was produced by the same method as in Example 1except that the solution (S6) was used instead of the solution (S1). Thegas barrier layer of the layered product (6) was transparent andcolorless and had a good surface appearance.

Next, the layered product (6) was subjected to the ionization treatmentusing the calcium acetate aqueous solution (MI-1) under the sameconditions as those employed in Example 1. Subsequently, superfluouscalcium acetate was washed away with distilled water whose temperaturehad been adjusted to 80° C. Thereafter, it was dried at 80° C. for fiveminutes. Thus, a layered product (B-6) of the present invention wasobtained. With respect to the layered product (B-6), the neutralizationdegree of the carboxyl groups of the polyacrylic acid contained in thegas barrier layer was determined by the aforementioned method. As aresult, it was proved that 70 mol % of the carboxyl groups had beenneutralized by calcium ions. With respect to the layered product (B-6),the oxygen barrier property, surface appearance, and content ofinorganic components were evaluated by the aforementioned methods.

Furthermore, using the layered product (B-6), a layered product (B-6-1)that had a structure of gas barrierlayer/AC/OPET/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 1. With respect to this layered product, the dropped bagbreaking strength, ionization degree after the retort processing, andoxygen transmission rate after the retort processing were measured. Theionization degree after the retort processing was 95 mol %, while theoxygen transmission rate after the retort processing was lower than 0.2cm³/m²·day·atm. Thus, with respect to the both, the layered productexhibited excellent values.

Example 7

Polyacrylic acid (PAA) with a number average molecular weight of 150,000was dissolved in distilled water, and thereby a polyacrylic acid aqueoussolution was obtained, in which the solid content concentration was 10wt %.

Next, 45.6 parts by weight of tetramethoxysilane (TMOS) was dissolved in54.6 parts by weight of methanol. Subsequently, 9.07 parts by weight ofgamma-glycidoxypropyltrimethoxysilane was dissolved therein. Thereafter,3.42 parts by weight of distilled water and 8.44 parts by weight of 0.1Nhydrochloric acid were added thereto. Thus, a sol was prepared. This wasallowed to undergo hydrolysis and condensation reactions at 10° C. forone hour while being stirred. The sol thus obtained was diluted with 123parts by weight of distilled water, which then was added promptly to 756parts by weight of the above-mentioned 10-wt % polyacrylic acid aqueoussolution that was being stirred. Thus a solution (S7) was obtained. Withrespect to this solution (S7), the storage stability was evaluated bythe method described above.

Next, a layered product (7) that had a structure of gas barrier layer (2μm)/AC/OPET (12 μm) was produced by the same method as in Example 1except that the solution (S7) was used instead of the solution (S1). Thegas barrier layer of the layered product (7) was transparent andcolorless and had a good surface appearance.

Next, the layered product (7) was subjected to the ionization treatmentusing the calcium acetate aqueous solution (MI-1) under the sameconditions as those employed in Example 1. Subsequently, superfluouscalcium acetate was washed away with distilled water whose temperaturehad been adjusted to 80° C. Thereafter, it was dried at 80° C. Thus, alayered product (B-7) of the present invention was obtained. Withrespect to the layered product (B-7), the neutralization degree of thecarboxyl groups of the polyacrylic acid contained in the gas barrierlayer was determined by the aforementioned method. As a result, it wasproved that 67 mol % of the carboxyl groups had been neutralized bycalcium ions. With respect to the layered product (B-7), the oxygenbarrier property, surface appearance, tensile strength and elongation,and content of inorganic components were evaluated by the aforementionedmethods.

Furthermore, using the layered product (B-7), a layered product (B-7-1)that had a structure of gas barrierlayer/AC/OPET/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 1. With respect to this layered product, the dropped bagbreaking strength, ionization degree after the retort processing, andoxygen transmission rate after the retort processing were measured. Theionization degree after the retort processing was 93 mol %, while theoxygen transmission rate after the retort processing was lower than 0.2cm³/m²·day·atm. Thus, with respect to the both, the layered productexhibited excellent values.

Example 8

Polyacrylic acid (PAA) with a number average molecular weight of 150,000was dissolved in distilled water, and thereby a polyacrylic acid aqueoussolution was obtained, in which the solid content concentration was 10wt %.

Next, 68.4 parts by weight of tetramethoxysilane (TMOS) was dissolved in78.7 parts by weight of methanol. Subsequently, 10.3 parts by weight ofgamma-aminopropyltrimethoxysilane was dissolved therein. Thereafter,5.13 parts by weight of distilled water and 12.7 parts by weight of 0.1Nhydrochloric acid were added thereto. Thus, a sol was prepared. This wasallowed to undergo hydrolysis and condensation reactions at 10° C. forone hour while being stirred. The sol thus obtained was diluted with 158parts by weight of distilled water, which then was added promptly to 667parts by weight of the above-mentioned 10-wt % polyacrylic acid aqueoussolution that was being stirred. Thus a solution (S8) was obtained. Withrespect to this solution (S8), the storage stability was evaluated bythe method described above.

Next, a layered product (8) that had a structure of gas barrier layer (2μm)/AC/OPET (12 μm) was produced by the same method as in Example 1except that the solution (S8) was used instead of the solution (S1). Thegas barrier layer of the layered product (8) was transparent andcolorless and had a good surface appearance.

Next, the layered product (8) was subjected to the ionization treatmentusing the calcium acetate aqueous solution (MI-1) under the sameconditions as those employed in Example 1. Subsequently, superfluouscalcium acetate was washed away with distilled water whose temperaturehad been adjusted to 80° C. Thereafter, it was dried at 80° C. for fiveminutes. Thus, a layered product (B-8) of the present invention wasobtained. With respect to the layered product (B-8), the neutralizationdegree of the carboxyl groups of the polyacrylic acid contained in thegas barrier layer was determined by the aforementioned method. As aresult, it was proved that 62 mol % of the carboxyl groups had beenneutralized by calcium ions. With respect to the layered product (B-8),the oxygen barrier property, surface appearance, tensile strength andelongation, and content of inorganic components were evaluated by theaforementioned methods.

Furthermore, using the layered product (B-8), a layered product (B-8-1)that had a structure of gas barrierlayer/AC/OPET/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 1. With respect to this layered product, the dropped bagbreaking strength, ionization degree after the retort processing, andoxygen transmission rate after the retort processing were measured. Theionization degree after the retort processing was 88 mol %, while theoxygen transmission rate after the retort processing was lower than 0.2cm³/m²·day·atm. Thus, with respect to the both, the layered productexhibited excellent values.

Example 9

Polyacrylic acid (PAA) with a number average molecular weight of 150,000and polyvinyl alcohol (PVA-105 (Trade Name), manufactured by KURARAYCO., LTD.; with a viscosity average degree of polymerization of 500)were dissolved in distilled water in such a manner that the weight ratiotherebetween was 97:3. Subsequently, ammonia water was added thereto toneutralize 1.5 mol % of the carboxyl groups of the polyacrylic acid.Thus, an aqueous polymer solution containing polyacrylic acid andpolyvinyl alcohol was obtained, in which the solid content concentrationwas 10 wt %.

Next, 68.4 parts by weight of tetramethoxysilane (TMOS) was dissolved in82.0 parts by weight of methanol. Subsequently, 13.6 parts by weight ofgamma-glycidoxypropyltrimethoxysilane was dissolved therein. Thereafter,5.13 parts by weight of distilled water and 12.7 parts by weight of 0.1Nhydrochloric acid were added thereto. Thus, a sol was prepared. This wasallowed to undergo hydrolysis and condensation reactions at 10° C. forone hour while being stirred. The sol thus obtained was diluted with 185parts by weight of distilled water, which then was added promptly to 634parts by weight of the above-mentioned aqueous polymer solution that wasbeing stirred. Thus a solution (S9) was obtained. With respect to thissolution (S9), the storage stability was evaluated by the methoddescribed above.

Next, a layered product (9) that had a structure of gas barrier layer (2μm)/AC/OPET (12 μm) was produced by the same method as in Example 1except that the solution (S9) was used instead of the solution (S1). Thegas barrier layer of the layered product (9) was transparent andcolorless and had a good surface appearance.

Next, the layered product (9) was subjected to the ionization treatmentusing the calcium acetate aqueous solution (MI-1) under the sameconditions as those employed in Example 1. Subsequently, superfluouscalcium acetate was washed away with distilled water whose temperaturehad been adjusted to 80° C. Thereafter, it was dried at 80° C. for fiveminutes. Thus, a layered product (B-9) of the present invention wasobtained. With respect to the layered product (B-9), the neutralizationdegree of the carboxyl groups of the polyacrylic acid contained in thegas barrier layer was determined by the aforementioned method. As aresult, it was proved that 58 mol % of the carboxyl groups had beenneutralized by calcium ions. With respect to the layered product (B-9),the oxygen barrier property, surface appearance, tensile strength andelongation, and content of inorganic components were evaluated by theaforementioned methods.

Furthermore, using the layered product (B-9), a layered product (B-9-1)that had a structure of gas barrierlayer/AC/OPET/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 1. With respect to this layered product, the dropped bagbreaking strength, ionization degree after the retort processing, andoxygen transmission rate after the retort processing were measured. Theionization degree after the retort processing was 91 mol %, while theoxygen transmission rate after the retort processing was lower than 0.2cm³/m²·day·atm. Thus, with respect to the both, the layered productexhibited excellent values.

Example 10

Polyacrylic acid (PAA) with a number average molecular weight of 150,000and starch (soluble starch manufactured by Wako Pure ChemicalIndustries, Ltd.) were dissolved in distilled water in such a mannerthat the weight ratio therebetween was 97:3. Subsequently, ammonia waterwas added thereto to neutralize 1.5 mol % of the carboxyl groups of thepolyacrylic acid. Thus, an aqueous polymer solution containingpolyacrylic acid and starch was obtained, in which the solid contentconcentration was 10 wt %.

Next, 68.4 parts by weight of tetramethoxysilane (TMOS) was dissolved in82.0 parts by weight of methanol. Subsequently, 13.6 parts by weight ofgamma-glycidoxypropyltrimethoxysilane was dissolved therein. Thereafter,5.13 parts by weight of distilled water and 12.7 parts by weight of 0.1Nhydrochloric acid were added thereto. Thus, a sol was prepared. This wasallowed to undergo hydrolysis and condensation reactions at 10° C. forone hour while being stirred. The sol thus obtained was diluted with 185parts by weight of distilled water, which then was added promptly to 634parts by weight of the above-mentioned aqueous polymer solution that wasbeing stirred. Thus a solution (S10) was obtained. With respect to thissolution (S10), the storage stability was evaluated by the methoddescribed above.

Next, a layered product (10) that had a structure of gas barrier layer(2 μm)/AC/OPET (12 μm) was produced by the same method as in Example 1except that the solution (S10) was used instead of the solution (S1).The gas barrier layer was transparent and colorless and had a goodsurface appearance.

Next, the layered product (10) was subjected to the ionization treatmentusing the calcium acetate aqueous solution (MI-1) under the sameconditions as those employed in Example 1. Subsequently, superfluouscalcium acetate was washed away with distilled water whose temperaturehad been adjusted to 80° C. Thereafter, it was dried at 80° C. for fiveminutes. Thus, a layered product (B-10) of the present invention wasobtained. With respect to the layered product (B-10), the neutralizationdegree of the carboxyl groups of the polyacrylic acid contained in thegas barrier layer was determined by the aforementioned method. As aresult, it was proved that 57 mol % of the carboxyl groups had beenneutralized by calcium ions. In addition, with respect to the layeredproduct (B-10), the oxygen barrier property, surface appearance, tensilestrength and elongation, and content of inorganic components wereevaluated by the aforementioned methods.

Furthermore, using the layered product (B-10), a layered product(B-10-1) that had a structure of gas barrierlayer/AC/OPET/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 1. With respect to this layered product, the dropped bagbreaking strength, ionization degree after the retort processing, andoxygen transmission rate after the retort processing were measured. Theionization degree after the retort processing was 92 mol %, while theoxygen transmission rate after the retort processing was lower than 0.2cm³/m²·day·atm. Thus, with respect to the both, the layered productexhibited excellent values.

Example 11

First, the solution (S1) was prepared by the same method as inExample 1. Using this solution (S1), a gas barrier layer was formed on abase material (OPET) by the following method.

First, a two-component anchor coating agent (AC; Takelac 3210 (TradeName) and Takenate A3072 (Trade Name), manufactured by Mitsui TakedaChemicals, Inc.) was applied to one surface of a drawn PET film (OPET;Lumirror (Trade Name), manufactured by Toray Industries, Inc.), whichthen was dried. The solution (S1) was applied onto this anchor coatlayer using a bar coater in such a manner as to form a layer with athickness of 1 μm after being dried. This was dried at 80° C. for fiveminutes. Thereafter, the same two-component anchor coating agent as thatdescribed above was applied to the other surface of the drawn PET film,which then was dried. This anchor coat layer was coated with thesolution (S1) using a bar coater in such a manner that the solution (S1)formed a layer with a thickness of 1 μm after being dried. This wasdried at 80° C. for five minutes. Thereafter, this was heat-treated indry air at 200° C. for five minutes. Thus, a layered product (11) thathad a structure of gas barrier layer (1 μm)/AC/OPET (12 μm)/AC/gasbarrier layer (1 μm) was obtained. The gas barrier layers weretransparent and colorless and had a good surface appearance.

Next, the layered product (11) was subjected to the ionization treatmentusing the calcium acetate aqueous solution (MI-1) under the sameconditions as those employed in Example 1. Subsequently, superfluouscalcium acetate was washed away with distilled water whose temperaturehad been adjusted to 80° C. Thereafter, it was dried at 80° C. for fiveminutes. Thus, a layered product (B-11) of the present invention wasobtained. With respect to the layered product (B-11), the neutralizationdegree of the carboxyl groups of the polyacrylic acid contained in thegas barrier layers was determined by the aforementioned method. As aresult, it was proved that 61 mol % of the carboxyl groups had beenneutralized by calcium ions. In addition, with respect to the layeredproduct (B-11), the oxygen barrier property, surface appearance, tensilestrength and elongation, and content of inorganic components wereevaluated by the aforementioned methods.

Furthermore, using the layered product (B-11), a layered product(B-11-1) that had a structure of gas barrier layer/AC/OPET/AC/gasbarrier layer/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 1. With respect to this layered product, the dropped bagbreaking strength, ionization degree after the retort processing, andoxygen transmission rate after the retort processing were measured. Theionization degree of the outermost layer after the retort processing was90 mol %, while the oxygen transmission rate after the retort processingwas lower than 0.2 cm³/m²·day·atm. Thus, with respect to the both, thelayered product exhibited excellent values.

Example 12

First, the layered product (1) described in Example 1 was produced. Thenthis layered product (1) was subjected to the ionization treatment underthe same conditions as those employed in Example 1 except that theperiod of time for immersing the layered product (1) in the calciumacetate aqueous solution was changed to approximately one second.Subsequently, superfluous calcium acetate was washed away with distilledwater whose temperature had been adjusted to 80° C. Thereafter, it wasdried at 80° C. for five minutes. Thus, a layered product (B-12) of thepresent invention was obtained. With respect to the layered product(B-12), the neutralization degree of the carboxyl groups of thepolyacrylic acid contained in the gas barrier layer was determined bythe aforementioned method. As a result, it was proved that 5 mol % ofthe carboxyl groups had been neutralized by calcium ions. In addition,with respect to the layered product (B-12) thus obtained, the oxygenbarrier property, surface appearance, tensile strength and elongation,and content of inorganic components were evaluated by the aforementionedmethods.

Furthermore, using the layered product (B-12), a layered product(B-12-1) that had a structure of gas barrierlayer/AC/OPET/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 1. With respect to this layered product, the dropped bagbreaking strength, ionization degree after the retort processing, andoxygen transmission rate after the retort processing were measured. Theionization degree after the retort processing was 5 mol %, while theoxygen transmission rate after the retort processing was 60cm³/m²·day·atm. In this example, the retort processing was carried outusing ion-exchanged water.

Example 13

First, the layered product (1) described in Example 1 was produced. Thenthis layered product (1) was subjected to the ionization treatment underthe same conditions as those employed in Example 1 except that theperiod of time for immersing the layered product (1) in the calciumacetate aqueous solution (MI-1) was changed from 20 seconds to threeseconds. Subsequently, superfluous calcium acetate was washed away withdistilled water whose temperature had been adjusted to 80° C.Thereafter, it was dried at 80° C. for five minutes. Thus, a layeredproduct (B-13) of the present invention was obtained. With respect tothe layered product (B-13), the neutralization degree of the carboxylgroups of the polyacrylic acid contained in the gas barrier layer wasdetermined by the aforementioned method. As a result, it was proved that15 mol % of the carboxyl groups had been neutralized by calcium ions. Inaddition, with respect to the layered product (B-13) thus obtained, theoxygen barrier property, surface appearance, tensile strength andelongation, and content of inorganic components were evaluated by theaforementioned methods.

Furthermore, using the layered product (B-13), a layered product(B-13-1) that had a structure of gas barrierlayer/AC/OPET/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 1. With respect to this layered product, the dropped bagbreaking strength, ionization degree after the retort processing, andoxygen transmission rate after the retort processing were measured. Theionization degree after the retort processing was 15 mol %. The oxygentransmission rate after the retort processing was good, specifically 12cm³/m²·day·atm. In this example, the retort processing was carried outusing ion-exchanged water.

Comparative Example 1

Using the layered product (4) produced in Example 4 that was notsubjected to the ionization treatment, a layered product that had astructure of gas barrier layer/AC/OPET/adhesive/ONy/adhesive/PP wasproduced by the same method as in Example 1. With respect to thislayered product, the dropped bag breaking strength, ionization degreeafter the retort processing, and oxygen transmission rate after theretort processing were measured. The ionization degree after the retortprocessing was 0%. The oxygen transmission rate after the retortprocessing was 87 cm³/m²·day·atm. The characteristics of this layeredproduct were poor as compared to those of the layered products ofExamples. In this comparative example, the retort processing was carriedout using ion-exchanged water. Table 2 below also shows the results ofthe evaluations of the oxygen barrier property, surface appearance,tensile strength, and the content of inorganic components of the layeredproduct (4).

Comparative Example 2

Polyacrylic acid (PAA) with a number average molecular weight of 150,000was dissolved in distilled water, and thereby a polyacrylic acid aqueoussolution was obtained, in which the solid content concentration was 10wt %.

Next, a layered product (polyacrylic acid (2 μm)/AC/OPET (12 μm)) wasproduced by the same method as in Example 1 except that theabove-mentioned 10-wt % polyacrylic acid aqueous solution was usedinstead of the solution (S1). The polyacrylic acid layer was transparentand colorless and had a good surface appearance.

Subsequently, calcium acetate was dissolved in distilled water in such amanner as to have a concentration of 10 wt %. This aqueous solution waskept warm at 80° C. Then, when the layered product was immersed in thisaqueous solution (80° C.), a part of the polyacrylic acid layer wasdissolved. Hence, further evaluations were not made.

Table 1 shows production conditions that were employed in theaforementioned examples and comparative examples. On the other hand,Table 2 shows the evaluation results and measurement results.

TABLE 1 Content of Univalent Carboxylic Added Polymer Inorganic IonCompound (A) Acid- Added Com- Added Added Polyvalent Ion ContainingAdded Amount ponents Ion Amount Compound (B) Amount Ion NeutralizationExamples Polymer Polymer [wt %] [wt %] Type [mol %] Type Type [mol %(*)] Type Degree Example 1 PAA — — 30 NH₄ ⁺ 1.5 TMOS a-1 10 Ca²⁺ 60Example 2 PAA — — 30 NH₄ ⁺ 1.5 TMOS a-1 10 Mg²⁺ 64 Example 3 PAA — — 30NH₄ ⁺ 1.5 TMOS a-1 10 Zn²⁺ 60 Example 4 PAA — — 30 — — TMOS a-1 10 Ca²⁺63 Example 5 PAA — — 30 — — TMOS a-1 20 Ca²⁺ 55 Example 6 PAA — — 8 — —— a-1 100 Ca²⁺ 70 Example 7 PAA — — 20 — — TMOS a-1 10 Ca²⁺ 67 Example 8PAA — — 30 — — TMOS a-2 10 Ca²⁺ 62 Example 9 PAA PVA 3 30 NH₄ ⁺ 1.5 TMOSa-1 10 Ca²⁺ 58 Example 10 PAA Starch 3 30 NH₄ ⁺ 1.5 TMOS a-1 10 Ca²⁺ 57Example 11 PAA — — 30 NH₄₊ 1.5 TMOS a-1 10 Ca²⁺ 61 Example 12 PAA — — 30— — TMOS a-1 10 Ca²⁺ 5 Example 13 PAA — — 30 — — TMOS a-1 10 Ca²⁺ 15Comparative PAA — — 30 — — TMOS a-1 10 — — Example 1 Comparative PAA — —0 — — — — — Ca²⁺ — Example 2 a-1: gamma-glycidoxypropyltrimethoxysilanea-2: gamma-aminopropyltrimethoxysilane (*) The ratio of Compound (A) tothe total of Compound (A) and Compound (B) [(Compound (A))/(Compound(A) + Compound (B))]

TABLE 2 Oxygen Rate of Transmission Increase in Rate Dropped TensileViscosity after Retort Bag Strength and of Solution Oxygen TransmissionRate Processing Breaking Elongation (S) (cm³/m² · day · atm) (cm³/m² ·Surface Strength Strength Elongation Examples (%) 65% RH 85% RH 95% RHday · atm) Appearance (Times) (MPa) (%) Example 1 2 0.4 0.4 0.5 0.2> AA115 140 220 Example 2 2 0.4 0.4 0.5 0.2> AA 117 140 200 Example 3 2 0.40.4 0.5 0.2> AA 110 130 220 Example 4 0 0.2 0.2 0.2 0.2> A 101 140 220Example 5 0 0.5 0.5 0.6 0.2> AA 94 120 180 Example 6 0 0.2 0.2 0.2 0.2>AA 82 100 160 Example 7 0 0.4 0.4 0.5 0.2> AA 96 120 170 Example 8 1 0.80.8 1.0 0.2> A 98 140 200 Example 9 1 0.2 0.2 0.2 0.2> AA 134 160 240Example 10 1 0.2 0.2 0.2 0.2> A 137 160 230 Example 11 2 0.7 0.7 0.80.2> A 98 130 190 Example 12 2 35 45 68 60 A 121 140 200 Example 13 2 1113 25 12 A 110 160 210 Comparative 1 38 52 83 87 A 112 140 200 Example 1Comparative — — — — — — — — — Example 2

As shown in Table 2, the layered products (B-1) to (B-13) of Examples 1to 13 each exhibited a higher oxygen barrier property than that of thelayered product (4) of Comparative Example 1 that was not subjected tothe ionization treatment, under all the humidity conditions. Among them,the layered products (B-1) to (B-11) and the layered product (B-13) ofExamples 1 to 11 and 13, particularly, the layered products (B-1) to(B-11) of Examples 1 to 11 each exhibited a higher oxygen barrierproperty under all the conditions without depending on humidity. Theselayered products also were transparent and had a good surfaceappearance. Furthermore, as compared to the film of the OPET singlelayer with no gas barrier layer formed thereon, these layered productswere not inferior in tensile strength and elongation and exhibited goodcharacteristics.

As shown in Table 2, the layered products (B-1-1) to (B-13-1) ofExamples 1 to 13 each had a higher oxygen barrier property even afterthe retort processing as compared to the layered product of ComparativeExample 1. Particularly, the layered products of Examples 1 to 11 and 13(especially Examples 1 to 11) each had a very high oxygen barrierproperty after the retort processing.

Furthermore, the layered products (B-1-1) to (B-13-1) having amultilayered structure that were produced in Examples 1 to 13 each hadhigh dropped bag breaking strength and high bending resistance.

Moreover, as shown in Table 2, the change in viscosity hardly was foundin the respective solutions (S1) to (S10) even after a lapse of twodays.

Example 14

First, the solution (S1) was prepared by the same method as inExample 1. Using this solution (S1), a gas barrier layer was formed on abase material (OPET) by the following method.

In a two-component anchor coating agent used herein, Takelac A3210(Trade Name) manufactured by Mitsui Takeda Chemicals, Inc. was used as apolyol base resin, and Takenate A3072 (Trade Name) manufactured byMitsui Takeda Chemicals, Inc. was used as an aromatic isocyanate curingagent. These base resin and curing agent as well as ethyl acetate (themoisture contained in ethyl acetate was 340 ppm) were mixed together insuch a manner that the weight ratio of the base resin/the curing agentwas 1/1. Thereafter, a drawn PET film (OPET; Lumirror (Trade Name),manufactured by Toray Industries, Inc.) was coated with the mixture,which then was dried. Thus a base material (AC/OPET) having an anchorcoat layer (an adhesive layer) with a thickness of 0.1 μm was produced.The anchor coat layer of this base material was coated with the solution(S1) using a bar coater in such a manner that the solution (S1) formed alayer with a thickness of 1 μm after being dried. This was dried at 80°C. for five minutes. Thereafter, the same two-component anchor coatingagent as that described above was applied to the other surface of thedrawn PET film to have the same thickness as that described above, whichthen was dried. This anchor coat layer was coated with the solution (S1)using a bar coater in such a manner that the solution (S1) formed alayer with a thickness of 1 μm after being dried. This was dried at 80°C. for five minutes. After that, this was heat-treated in dry air at200° C. for five minutes. Thus a layered product (14) that had astructure of gas barrier layer (1 μm)/AC (0.1 μm)/OPET (12 μm)/AC (0.1μm)/gas barrier layer (1 μm) was obtained. The gas barrier layers weretransparent and colorless and had a good surface appearance.

Next, the layered product (14) was subjected to the ionization treatmentusing the calcium acetate aqueous solution (MI-1) under the sameconditions as those employed in Example 1. Subsequently, superfluouscalcium acetate was washed away with distilled water whose temperaturehad been adjusted to 80° C. Thereafter, it was dried at 80° C. for fiveminutes. Thus, a layered product (B-14) of the present invention wasobtained. With respect to the layered product (B-14), the neutralizationdegree of the carboxyl groups of the polyacrylic acid contained in thegas barrier layers was determined by the aforementioned method. As aresult, it was proved that 61 mol % of the carboxyl groups had beenneutralized by calcium ions. In addition, with respect to the layeredproduct (B-14), the oxygen barrier property, surface appearance, changein appearance caused through heating, tensile strength and elongation,haze, and content of inorganic components were evaluated by theaforementioned methods.

Furthermore, using the layered product (B-14), a layered product(B-14-1) that had a structure of gas barrier layer/AC/OPET/AC/gasbarrier layer/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 1. With respect to this layered product, the dropped bagbreaking strength, peel strength, ionization degree after the retortprocessing, and oxygen transmission rate after the retort processingwere measured. The ionization degree of the outermost layer after theretort processing was 93 mol %, while the oxygen transmission rate afterthe retort processing was lower than 0.2 cm³/m²·day·atm. Thus, withrespect to the both, the layered product exhibited excellent values.

Example 15

A layered product (15) that had a structure of gas barrier layer (1μm)/AC (0.2 μm)/OPET (12 μm)/AC (0.2 μm)/gas barrier layer (1 μm) wasobtained by the same method as in Example 14 except that the thicknessof the anchor coat layer was changed to 0.2 μm. The gas barrier layerswere transparent and colorless and had a good surface appearance.

Next, the layered product (15) was subjected to the ionization treatmentusing the calcium acetate aqueous solution (MI-1) under the sameconditions as those employed in Example 1. Subsequently, superfluouscalcium acetate was washed away with distilled water whose temperaturehad been adjusted to 80° C. Thereafter, it was dried at 80° C. for fiveminutes. Thus, a layered product (B-15) of the present invention wasobtained. With respect to the layered product (B-15), the neutralizationdegree of the carboxyl groups of the polyacrylic acid contained in thegas barrier layers was determined by the aforementioned method. As aresult, it was proved that 61 mol % of the carboxyl groups had beenneutralized by calcium ions. In addition, with respect to the layeredproduct (B-15), the oxygen barrier property, surface appearance, changein appearance through heating, tensile strength and elongation, haze,and content of inorganic components were evaluated by the aforementionedmethods.

Furthermore, using the layered product (B-15), a layered product(B-15-1) that had a structure of gas barrier layer/AC/OPET/AC/gasbarrier layer/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 1. With respect to this layered product, the dropped bagbreaking strength, peel strength, ionization degree after the retortprocessing, and oxygen transmission rate after the retort processingwere measured. The ionization degree of the outermost layer after theretort processing was 90 mol %, while the oxygen transmission rate afterthe retort processing was lower than 0.2 cm³/m²·day·atm. Thus, withrespect to the both, the layered product exhibited excellent values.

Example 16

A layered product (16) that had a structure of gas barrier layer (1μm)/AC (0.1 μm)/OPET (12 μm)/AC (0.1 μm)/gas barrier layer (1 μm) wasobtained by the same method as in Example 14 except that with respect tothe base resin and the curing agent of the two-component anchor coatingagent and ethyl acetate (the moisture contained in ethyl acetate was 320ppm), the weight ratio between the base resin and the curing agent waschanged to 3/1 (the base resin/the curing agent). The gas barrier layerswere transparent and colorless and had a good surface appearance.

Next, the layered product (16) was subjected to the ionization treatmentusing the calcium acetate aqueous solution (MI-1) under the sameconditions as those employed in Example 1. Subsequently, superfluouscalcium acetate was washed away with distilled water whose temperaturehad been adjusted to 80° C. Thereafter, it was dried at 80° C. for fiveminutes. Thus, a layered product (B-16) of the present invention wasobtained. With respect to the layered product (B-16), the neutralizationdegree of the carboxyl groups of the polyacrylic acid contained in thegas barrier layers was determined by the aforementioned method. As aresult, it was proved that 61 mol % of the carboxyl groups had beenneutralized by calcium ions. In addition, with respect to the layeredproduct (B-16), the oxygen barrier property, surface appearance, changein appearance through heating, tensile strength and elongation, haze,and content of inorganic components were evaluated by the aforementionedmethods.

Furthermore, using the layered product (B-16), a layered product(B-16-1) that had a structure of gas barrier layer/AC/OPET/AC/gasbarrier layer/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 1. With respect to this layered product, the dropped bagbreaking strength, peel strength, ionization degree after the retortprocessing, and oxygen transmission rate after the retort processingwere measured. The ionization degree of the outermost layer after theretort processing was 90 mol %, while the oxygen transmission rate afterthe retort processing was lower than 0.2 cm³/m²·day·atm. Thus, withrespect to the both, the layered product exhibited excellent values.

Example 17

A layered product (17) that had a structure of gas barrier layer (1μm)/AC (0.1 μm)/OPET (12 μm)/AC (0.1 μm)/gas barrier layer (1 μm) wasobtained by the same method as in Example 14 except that the base resinand the curing agent of the two-component anchor coating agent and ethylacetate (the moisture contained in ethyl acetate was 5000 ppm) weremixed together in such a manner that the weight ratio between the baseresin and the curing agent was 1/1 (the base resin/the curing agent).The gas barrier layers were transparent and colorless and had a goodsurface appearance.

Next, the layered product (17) was subjected to the ionization treatmentusing the calcium acetate aqueous solution (MI-1) under the sameconditions as those employed in Example 1. Subsequently, superfluouscalcium acetate was washed away with distilled water whose temperaturehad been adjusted to 80° C. Thereafter, it was dried at 80° C. for fiveminutes. Thus, a layered product (B-17) of the present invention wasobtained. With respect to the layered product (B-17), the neutralizationdegree of the carboxyl groups of the polyacrylic acid contained in thegas barrier layers was determined by the aforementioned method. As aresult, it was proved that 61 mol % of the carboxyl groups had beenneutralized by calcium ions. In addition, with respect to the layeredproduct (B-17), the oxygen barrier property, peel strength, surfaceappearance, change in appearance through heating, tensile strength andelongation, haze, and content of inorganic components were evaluated bythe aforementioned methods.

Furthermore, using the layered product (B-17), a layered product(B-17-1) that had a structure of gas barrier layer/AC/OPET/AC/gasbarrier layer/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 1. With respect to this layered product, the dropped bagbreaking strength, peel strength, ionization degree after the retortprocessing, and oxygen transmission rate after the retort processingwere measured. The ionization degree of the outermost layer after theretort processing was 90 mol %, while the oxygen transmission rate afterthe retort processing was lower than 0.2 cm³/m²·day·atm. Thus, withrespect to the both, the layered product exhibited excellent values.

Example 18

A layered product (18) that had a structure of gas barrier layer (1μm)/AC (0.1 μm)/OPET (12 μm)/AC (0.1 μm)/gas barrier layer (1 μm) wasobtained by the same method as in Example 14 except that the anchorcoating agent used in this example was different from that used inExample 14. The gas barrier layers were transparent and colorless andhad a good surface appearance. The anchor coating agent employed inExample 18 was a two-component anchor coating agent in which a polyolbase resin and an aliphatic isocyanate curing agent that was lesssusceptible to the effect of moisture contained in an organic solventwere used. Takelac A626 (Trade Name) manufactured by Mitsui TakedaChemicals, Inc. was used as the base resin, while Takenate A50 (TradeName) manufactured by Mitsui Takeda Chemicals, Inc. was used as thecuring agent. The base resin, the curing agent, and ethyl acetate (themoisture contained in ethyl acetate was 1200 ppm) were mixed together insuch a manner that the weight ratio between the base resin and thecuring agent was 4/3 (the base resin/the curing agent).

Next, the layered product (18) was subjected to the ionization treatmentusing the calcium acetate aqueous solution (MI-1) under the sameconditions as those employed in Example 1. Subsequently, superfluouscalcium acetate was washed away with distilled water whose temperaturehad been adjusted to 80° C. Thereafter, it was dried at 80° C. for fiveminutes. Thus, a layered product (B-18) of the present invention wasobtained. With respect to the layered product (B-18), the neutralizationdegree of the carboxyl groups of the polyacrylic acid contained in thegas barrier layers was determined by the aforementioned method. As aresult, it was proved that 61 mol % of the carboxyl groups had beenneutralized by calcium ions. In addition, with respect to the layeredproduct (B-18), the oxygen barrier property, surface appearance, changein appearance through heating, tensile strength and elongation, haze,and content of inorganic components were evaluated by the aforementionedmethods.

Furthermore, using the layered product (B-18), a layered product(B-18-1) that had a structure of gas barrier layer/AC/OPET/AC/gasbarrier layer/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 1. With respect to this layered product, the dropped bagbreaking strength, peel strength, ionization degree after the retortprocessing, and oxygen transmission rate after the retort processingwere measured. The ionization degree of the outermost layer after theretort processing was 90 mol %, while the oxygen transmission rate afterthe retort processing was lower than 0.2 cm³/m²·day·atm. Thus, withrespect to the both, the layered product exhibited excellent values.

Example 19

First, the solution (S1) was prepared by the same method as in Example1.

The anchor coating agent employed in this example was a two-componentanchor coating agent in which a polyol base resin and an aliphaticisocyanate curing agent that was less susceptible to the effect ofmoisture contained in an organic solvent were used. Takelac A626 (TradeName) manufactured by Mitsui Takeda Chemicals, Inc. was used as the baseresin, while Takenate A50 (Trade Name) manufactured by Mitsui TakedaChemicals, Inc. was used as the curing agent. The base resin, the curingagent, and ethyl acetate (the moisture contained in ethyl acetate was560 ppm) were mixed together in such a manner that the weight ratiobetween the base resin and the curing agent was 4/3 (the base resin/thecuring agent). Thereafter, a drawn PET film (OPET; Lumirror (TradeName), manufactured by Toray Industries, Inc.) was coated with themixture, which then was dried. Thus a base material (AC/OPET) having ananchor coat layer (an adhesive layer) with a thickness of 0.1 μm wasproduced.

Next, an aluminum oxide layer (with a thickness of 30 nm) wasvapor-deposited on the anchor coat layer in a vacuum vapor depositionapparatus that employed an electron beam heating system. Subsequently,the aluminum oxide layer was coated with the solution (S1) using a barcoater in such a manner that the solution (S1) formed a layer with athickness of 1 μm after being dried. This was dried at 80° C. for fiveminutes. After that, this was heat-treated in dry air at 200° C. forfive minutes. Thus a layered product (19) that had a structure of gasbarrier layer (1 μm)/aluminum oxide layer/AC/OPET (12 μm) was obtained.The gas barrier layer was transparent and colorless and had a goodsurface appearance.

Next, the layered product (19) was subjected to the ionization treatmentusing the calcium acetate aqueous solution (MI-1) under the sameconditions as those employed in Example 1. Subsequently, superfluouscalcium acetate was washed away with distilled water whose temperaturehad been adjusted to 80° C. Thereafter, it was dried at 80° C. for fiveminutes. Thus, a layered product (B-19) of the present invention wasobtained. With respect to the layered product (B-19), the neutralizationdegree of the carboxyl groups of the polyacrylic acid contained in thegas barrier layer was determined by the aforementioned method. As aresult, it was proved that 61 mol % of the carboxyl groups had beenneutralized by calcium ions. In addition, with respect to the layeredproduct (B-19), the oxygen barrier property, surface appearance, changein appearance through heating, tensile strength and elongation, haze,and content of inorganic components were evaluated by the aforementionedmethods.

Furthermore, using the layered product (B-19), a layered product(B-19-1) that had a structure of OPET/AC/vapor-deposited thin filmlayer/gas barrier layer/adhesive/ONy/adhesive/PP was produced by thesame method as in Example 1. With respect to this layered product, thedropped bag breaking strength, peel strength, ionization degree afterthe retort processing, and oxygen transmission rate after the retortprocessing were measured. The ionization degree of the outermost layerafter the retort processing was 90 mol %, while the oxygen transmissionrate after the retort processing was lower than 0.2 cm³/m²·day·atm.Thus, with respect to the both, the layered product exhibited excellentvalues.

Example 20

First, the solution (S1) was prepared by the same method as in Example1.

The anchor coating agent employed in this example was a two-componentanchor coating agent in which a polyol base resin and an aliphaticisocyanate curing agent were used. Takelac A626 (Trade Name)manufactured by Mitsui Takeda Chemicals, Inc. was used as the baseresin, while Takenate A50 (Trade Name) manufactured by Mitsui TakedaChemicals, Inc. was used as the curing agent. The base resin, the curingagent, and ethyl acetate (the moisture contained in ethyl acetate was620 ppm) were mixed together in such a manner that the weight ratiobetween the base resin and the curing agent was 4/3 (the base resin/thecuring agent). Thereafter, a drawn PET film (OPET; Lumirror (TradeName), manufactured by Toray Industries, Inc.) was coated with themixture, which then was dried. Thus a base material (AC/OPET) having ananchor coat layer (an adhesive layer) with a thickness of 0.1 μm wasproduced.

Next, a silicon oxide layer (with a thickness of 25 nm) wasvapor-deposited on the anchor coat layer in a vacuum vapor depositionapparatus that employed an electron beam heating system. Subsequently,the silicon oxide layer was coated with the solution (S1) using a barcoater in such a manner that the solution (S1) formed a layer with athickness of 1 μm after being dried. This was dried at 80° C. for fiveminutes. After that, this was heat-treated in dry air at 200° C. forfive minutes. Thus a layered product (20) that had a structure of gasbarrier layer (1 μm)/silicon oxide layer/AC/OPET (12 μm) was obtained.The gas barrier layer was transparent and colorless and had a goodsurface appearance.

Next, the layered product (20) was subjected to the ionization treatmentusing the calcium acetate aqueous solution (MI-1) under the sameconditions as those employed in Example 1. Subsequently, superfluouscalcium acetate was washed away with distilled water whose temperaturehad been adjusted to 80° C. Thereafter, it was dried at 80° C. for fiveminutes. Thus, a layered product (B-20) of the present invention wasobtained. With respect to the layered product (B-20), the neutralizationdegree of the carboxyl groups of the polyacrylic acid contained in thegas barrier layer was determined by the aforementioned method. As aresult, it was proved that 60 mol % of the carboxyl groups had beenneutralized by calcium ions. In addition, with respect to the layeredproduct (B-20), the oxygen barrier property, surface appearance, changein appearance through heating, tensile strength and elongation, haze,and content of inorganic components were evaluated by the aforementionedmethods.

Furthermore, using the layered product (B-20), a layered product (B-)that had a structure of OPET/AC/vapor-deposited thin film layer/gasbarrier layer/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 1. With respect to this layered product, the dropped bagbreaking strength, peel strength, ionization degree after the retortprocessing, and oxygen transmission rate after the retort processingwere measured. The ionization degree of the outermost layer after theretort processing was 88 mol %, while the oxygen transmission rate afterthe retort processing was lower than 0.2 cm³/m²·day·atm. Thus, withrespect to the both, the layered product exhibited excellent values.

Example 21

A layered product (21) that had a structure of gas barrier layer (1μm)/AC (0.1 μm)/OPET (12 μm)/AC (0.1 μm)/gas barrier layer (1 μm) wasobtained by the same method as in Example 14 except that the heattreatment to be carried out at 200° C. for five minutes was notperformed. The gas barrier layers were transparent and colorless and hada good surface appearance.

Next, the layered product (21) was subjected to the ionization treatmentusing the calcium acetate aqueous solution (MI-1) under the sameconditions as those employed in Example 1. Subsequently, superfluouscalcium acetate was washed away with distilled water whose temperaturehad been adjusted to 80° C. Thereafter, it was dried at 80° C. for fiveminutes. Thus, a layered product (B-21) of the present invention wasobtained. With respect to the layered product (B-21), the neutralizationdegree of the carboxyl groups of the polyacrylic acid contained in thegas barrier layers was determined by the aforementioned method. As aresult, it was proved that 94 mol % of the carboxyl groups had beenneutralized by calcium ions. In addition, with respect to the layeredproduct (B-21), the oxygen barrier property, surface appearance, changein appearance through heating, tensile strength and elongation, haze,and content of inorganic components were evaluated by the aforementionedmethods.

Furthermore, using the layered product (B-21), a layered product(B-21-1) that had a structure of gas barrier layer/AC/OPET/AC/gasbarrier layer/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 1. With respect to this layered product, the dropped bagbreaking strength, peel strength, ionization degree after the retortprocessing, and oxygen transmission rate after the retort processingwere measured. The ionization degree of the outermost layer after theretort processing was 96 mol %, while the oxygen transmission rate afterthe retort processing was lower than 0.3 cm³/m²·day·atm. With respect tothe both, the layered product exhibited excellent values. In addition,the oxygen transmission rate after the retort processing that wascarried out using ion-exchanged water was 0.3 cm³/m²·day·atm.

Example 22

A layered product (22) that had a structure of gas barrier layer (1μm)/AC (0.1 μm)/OPET (12 μm)/AC (0.1 μm)/gas barrier layer (1 μm) wasobtained by the same method as in Example 14. The gas barrier layerswere transparent and colorless and had a good surface appearance.

Next, the layered product (22) was subjected to the ionization treatmentunder the same conditions as those employed in Example 1 except that theperiod of time for which the ionization treatment was carried out was300 seconds. Subsequently, superfluous calcium acetate was washed awaywith distilled water whose temperature had been adjusted to 80° C.Thereafter, it was dried at 80° C. for five minutes. Thus, a layeredproduct (B-22) of the present invention was obtained. With respect tothe layered product (B-22), the neutralization degree of the carboxylgroups of the polyacrylic acid contained in the gas barrier layers wasdetermined by the aforementioned method. As a result, it was proved that97 mol % of the carboxyl groups had been neutralized by calcium ions. Inaddition, with respect to the layered product (B-22), the oxygen barrierproperty, surface appearance, change in appearance through heating,tensile strength and elongation, haze, and content of inorganiccomponents were evaluated by the aforementioned methods.

Furthermore, using the layered product (B-22), a layered product(B-22-1) that had a structure of gas barrier layer/AC/OPET/AC/gasbarrier layer/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 1. With respect to this layered product, the dropped bagbreaking strength, peel strength, ionization degree after the retortprocessing, and oxygen transmission rate after the retort processingwere measured. The ionization degree of the outermost layer after theretort processing was 93 mol %, while the oxygen transmission rate afterthe retort processing was lower than 0.2 cm³/m²·day·atm. Thus, withrespect to the both, the layered product exhibited excellent values. Inthis example, the retort processing was carried out using ion-exchangedwater.

Comparative Example 3

A layered product that had a structure of gas barrier layer (1 μm)/AC(0.1 μm)/OPET (12 μm)/AC (0.1 μm)/gas barrier layer (1 μm) was obtainedby the same method as in Example 14. The gas barrier layers weretransparent and colorless and had a good surface appearance.

The layered product thus obtained was subjected to a neutralizationtreatment using a sodium acetate aqueous solution as described below.First, sodium acetate was dissolved in distilled water in such a manneras to have a concentration of 10 wt %. This aqueous solution was keptwarm at 80° C. Then, the above-mentioned layered product was immersed inthis aqueous solution for approximately 20 seconds. Thereafter, thislayered product was removed therefrom. Then the surfaces of the layeredproduct were washed with distilled water whose temperature had beenadjusted to 80° C. After that, it was dried at 80° C. for five minutes.Thus, a layered product (C3) was obtained. With respect to the layeredproduct (C3), the neutralization degree of the carboxyl groups of thepolyacrylic acid contained in the gas barrier layers was determined bythe aforementioned method. As a result, it was proved that 63 mol % ofthe carboxyl groups had been neutralized by sodium ions. With respect tothe layered product (C3) thus obtained, the oxygen barrier property,surface appearance, tensile strength and elongation, and the content ofinorganic components were evaluated by the aforementioned methods.

Furthermore, using the layered product (C3), a layered product (C-3-1)that had a structure of gas barrier layer/AC/OPET/AC/gas barrierlayer/adhesive/ONy/adhesive/PP was produced by the same method as inExample 1. With respect to this layered product, the dropped bagbreaking strength, peel strength, ionization degree after the retortprocessing, and oxygen transmission rate after the retort processingwere measured. The ionization degree of the outermost layer after theretort processing was 63 mol %, while the oxygen transmission rate afterthe retort processing was 84 cm³/m²·day·atm. In this comparativeexample, the retort processing was carried out using ion-exchangedwater.

Table 3 indicates the production conditions of Examples 14 to 21 andComparative Example 3. In addition, Table 4 indicates the evaluationsresults and measurement results. The content of nitrogen in the anchorcoating agent was determined from ultimate analysis.

TABLE 3 Univalent AC Layer Content Ion Carboxylic Content of Com-Compound (A) Acid- of Inorganic Added pound Added Polyvalent IonContaining Nitrogen Thickness Layer Components Ion Amount (B) Amount IonNeutralization Examples Polymer (wt %) [μm] Structure [wt %] Type [mol%] Type Type [mol % (*)] Type Degree Example PAA 7.9 0.1 Both 30 NH₄ ⁺1.5 TMOS a-1 10 Ca²⁺ 61 14 Sides Example PAA 7.9 0.2 Both 30 NH₄ ⁺ 1.5TMOS a-1 10 Ca²⁺ 61 15 Sides Example PAA 4.4 0.1 Both 30 NH₄ ⁺ 1.5 TMOSa-1 10 Ca²⁺ 61 16 Sides Example PAA 7.2 0.1 Both 30 NH₄ ⁺ 1.5 TMOS a-110 Ca²⁺ 61 17 Sides Example PAA 4.9 0.1 Both 30 NH₄ ⁺ 1.5 TMOS a-1 10Ca²⁺ 61 18 Sides Example PAA 4.9 0.1 One Side 30 NH₄ ⁺ 1.5 TMOS a-1 10Ca²⁺ 61 19 Example PAA 4.9 0.1 One Side 30 NH₄ ⁺ 1.5 TMOS a-1 10 Ca²⁺ 6020 Example PAA 7.2 0.1 Both 30 NH₄ ⁺ 1.5 TMOS a-1 10 Ca²⁺ 94 21 SidesExample PAA 7.2 0.1 Both 30 NH₄ ⁺ 1.5 TMOS a-1 10 Ca²⁺ 97 22 SidesComparative PAA 7.2 0.1 Both 30 NH₄ ⁺ 1.5 TMOS a-1 10 (Na⁺) (63) Example3 Sides a-1: gamma-glycidoxypropyltrimethoxysilane (*) The ratio ofCompound (A) to the total of Compound (A) and Compound (B) [(Compound(A))/(Compound (A) + Compound (B))]

TABLE 4 Rate of Increase Oxygen Oxygen in Transmission TransmissionViscosity Rate Rate Dropped of (cm³/m² · after Retort Surface BagTensile Strength Solution day · atm) Processing 3σ Appearance PeelBreaking and Elongation (S) 65% 85% 95% (cm³/m² · of Surface AfterStrength Strength Strength Elongation Examples (%) RH RH RH day · atm)Haze Appearance Heating [g/15 mm] (Times) (MPa) (%) Example 2 0.4 0.40.5 0.2> 0.63 AA AA 570 120 140 210 14 Example 2 0.4 0.4 0.5 0.2> 0.60AA B 630 130 130 180 15 Example 2 0.4 0.4 0.5 0.2> 0.60 AA A 550 110 130220 16 Example 2 0.4 0.4 0.5 0.2> 2.40 A A 250 78 140 220 17 Example 20.4 0.4 0.5 0.2> 0.30 AA AA 560 125 120 190 18 Example 2 0.2> 0.2> 0.2>0.2> 0.30 AA AA 380 73 120 200 19 Example 2 0.2> 0.2> 0.2> 0.2> 0.30 AAAA 360 81 110 200 20 Example 2 0.2> 0.2> 0.2> 0.2> 0.60 AA B 570 52 120220 21 Example 2 0.2> 0.2> 0.2> 0.2> 0.62 AA AA 600 118 140 200 22Comparative 2 84 87 89 87 0.59 AA AA 590 110 140 190 Example 3

Example 23

Polyacrylic acid (PAA) with a number average molecular weight of 150,000was dissolved in distilled water. Thereafter, ammonia water was addedthereto and thereby 1.5 mol % of the carboxyl groups of the polyacrylicacid were neutralized. Thus, a polyacrylic acid aqueous solution wasobtained, in which the solid content concentration was 10 wt %.

Next, 68.4 parts by weight of tetramethoxysilane (TMOS) was dissolved in79.8 parts by weight of methanol. Subsequently, 11.4 parts by weight of3-chloropropyltrimethoxysilane (manufactured by Chisso Corporation) wasdissolved therein. Thereafter, 5.13 parts by weight of distilled waterand 12.7 parts by weight of 0.1N hydrochloric acid were added thereto.Thus, a sol was prepared. This was allowed to undergo hydrolysis andcondensation reactions at 10° C. for one hour while being stirred. Thesol thus obtained was diluted with 189 parts by weight of distilledwater, which then was added promptly to 657 parts by weight of theabove-mentioned 10-wt % polyacrylic acid aqueous solution that was beingstirred. Thus a solution (S23) was obtained.

On the other hand, a drawn PET film (OPET) was coated with atwo-component anchor coating agent (Takelac 3210 (Trade Name) andTakenate A3072 (Trade Name), manufactured by Mitsui Takeda Chemicals,Inc.), which then was dried. Thus a base material (AC/OPET) having ananchor coat layer was produced. The anchor coat layer of the basematerial was coated with the solution (S23) using a bar coater in such amanner that the solution (S23) formed a layer with a thickness of 2 μmafter being dried. This was dried at 80° C. for five minutes and thenwas heat-treated in dry air at 200° C. for five minutes. Thus, a layeredproduct (23) that had a structure of gas barrier layer (2 μm)/AC/OPET(12 μm) was obtained. The gas barrier layer was transparent andcolorless and had an excellent appearance.

Next, calcium acetate was dissolved in distilled water in such a manneras to have a concentration of 10 wt %. This aqueous solution was keptwarm at 80° C. Then, the layered product (23) was immersed in thisaqueous solution (80° C.; MI-1) for approximately five seconds.Thereafter, this layered product was removed therefrom. Then thesurfaces of the layered product were washed with distilled water whosetemperature had been adjusted to 80° C. After that, it was dried at 80°C. for five seconds. Thus, a layered product (B-23) of the presentinvention was obtained. With respect to the layered product (B-23), theneutralization degree of the carboxyl groups of the polyacrylic acidcontained in the gas barrier layer was determined by the aforementionedmethod. As a result, it was proved that 69 mol % of the carboxyl groupshad been neutralized by calcium ions. With respect to the layeredproduct (B-23) thus obtained, the oxygen barrier property, haze, and thecontent of inorganic components were evaluated by the aforementionedmethods.

Furthermore, an drawn nylon film (Emblem (Trade Name), manufactured byUnitika, Ltd.; with a thickness of 15 μm; hereinafter may be abbreviatedas “ONy” in some cases) and a polypropylene film (RXC-18 (Trade Name),manufactured by Tohcello Co., Ltd.; with a thickness of 50 μm;hereinafter may be abbreviated as “PP” in some cases) each were coatedwith a two-component adhesive (A-385 (Trade Name) and A-50 (Trade Name),manufactured by Mitsui Takeda Chemicals, Inc.), which then were dried.Then the films thus obtained were laminated with the above-mentionedlayered product (B-23; gas barrier layer/AC/OPET). Thus, a layeredproduct (B-23-1) that had a structure of gas barrierlayer/AC/OPET/adhesive/ONy/adhesive/PP was obtained. Using this layeredproduct, the neutralization degree after the retort processing and theoxygen transmission rate after the retort processing were measured. Theneutralization degree after the retort processing was 92 mol %, whilethe oxygen transmission rate after the retort processing was lower than0.2 cm³/m²·day·atm. Thus, with respect to the both, the layered productexhibited excellent values.

Example 24

Polyacrylic acid (PAA) with a number average molecular weight of 150,000was dissolved in distilled water. Thereafter, ammonia water was addedthereto and thereby 1.5 mol % of the carboxyl groups of the polyacrylicacid were neutralized. Thus, a polyacrylic acid aqueous solution wasobtained, in which the solid content concentration was 10 wt %.

Next, 68.4 parts by weight of tetramethoxysilane was dissolved in 79.7parts by weight of methanol. Subsequently, 11.3 parts by weight of3-mercaptopropyltrimethoxysilane (manufactured by Chisso Corporation)was dissolved therein. Thereafter, 5.13 parts by weight of distilledwater and 12.7 parts by weight of 0.1N hydrochloric acid were addedthereto. Thus, a sol was prepared. This was allowed to undergohydrolysis and condensation reactions at 10° C. for one hour while beingstirred. The sol thus obtained was diluted with 189 parts by weight ofdistilled water, which then was added promptly to 658 parts by weight ofthe above-mentioned 10-wt % polyacrylic acid aqueous solution that werebeing stirred. Thus a solution (S24) was obtained. With respect to thissolution (S24), the storage stability was evaluated by the methoddescribed above.

Next, a layered product (24) that had a structure of gas barrier layer(2 μm)/AC/OPET (12 μm) was produced by the same method as in Example 23except that the solution (S24) was used instead of the solution (S23).The gas barrier layer of the layered product (24) was transparent andcolorless and had an excellent surface appearance.

Next, the layered product (24) was subjected to the ionization treatmentusing the calcium acetate aqueous solution (MI-1) under the sameconditions as those employed in Example 23. Subsequently, superfluouscalcium acetate was washed away with distilled water whose temperaturehad been adjusted to 80° C. Thereafter, it was dried at 80° C. for fiveminutes. Thus, a layered product (B-24) of the present invention wasobtained. With respect to the layered product (B-24), the neutralizationdegree of the carboxyl groups of the polyacrylic acid contained in thegas barrier layer was determined by the aforementioned method. As aresult, it was proved that 86 mol % of the carboxyl groups had beenneutralized by calcium ions. In addition, with respect to the layeredproduct (B-24), the oxygen barrier property, haze, and content ofinorganic components were evaluated by the aforementioned methods.

Furthermore, using the layered product (B-24), a layered product(B-24-1) that had a structure of gas barrierlayer/AC/OPET/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 23. With respect to this layered product, theneutralization degree after the retort processing and the oxygentransmission rate after the retort processing were measured. Theneutralization degree after the retort processing was 95 mol %, whilethe oxygen transmission rate after the retort processing was lower than0.2 cm³/m²·day·atm. Thus, with respect to the both, the layered productexhibited excellent values.

Example 25

Polyacrylic acid (PAA) with a number average molecular weight of 150,000was dissolved in distilled water. Thereafter, ammonia water was addedthereto and thereby 1.5 mol % of the carboxyl groups of the polyacrylicacid were neutralized. Thus, a polyacrylic acid aqueous solution wasobtained, in which the solid content concentration was 10 wt %.

Next, 68.4 parts by weight of tetramethoxysilane was dissolved in 68.4parts by weight of methanol. Subsequently, 23.0 parts by weight of a 50%ethanol solution of N-(3-triethoxysilylpropyl)gluconamide (sold byChisso Corporation) was dissolved therein. Thereafter, 5.13 parts byweight of distilled water and 12.7 parts by weight of 0.1N hydrochloricacid were added thereto. Thus, a sol was prepared. This was allowed toundergo hydrolysis and condensation reactions at 10° C. for one hourwhile being stirred. The sol thus obtained was diluted with 189 parts byweight of distilled water, which then was added promptly to 541 parts byweight of the above-mentioned 10-wt % polyacrylic acid aqueous solutionthat were being stirred. Thus a solution (S25) was obtained. Withrespect to this solution (S25), the storage stability was evaluated bythe method described above.

Next, a layered product (25) that had a structure of gas barrier layer(2 μm)/AC/OPET (12 μm) was produced by the same method as in Example 23except that the solution (S25) was used instead of the solution (S23).The gas barrier layer of the layered product (25) was transparent andcolorless and had an excellent surface appearance.

Next, the layered product (25) was subjected to the ionization treatmentusing the calcium acetate aqueous solution (MI-1) under the sameconditions as those employed in Example 23. Subsequently, superfluouscalcium acetate was washed away with distilled water whose temperaturehad been adjusted to 80° C. Thereafter, it was dried at 80° C. for fiveminutes. Thus, a layered product (B-25) of the present invention wasobtained. With respect to the layered product (B-25), the neutralizationdegree of the carboxyl groups of the polyacrylic acid contained in thegas barrier layer was determined by the aforementioned method. As aresult, it was proved that 50 mol % of the carboxyl groups had beenneutralized by calcium ions. In addition, with respect to the layeredproduct (B-25), the oxygen barrier property, haze, and content ofinorganic components were evaluated by the aforementioned methods.

Furthermore, using the layered product (B-25), a layered product(B-25-1) that had a structure of gas barrierlayer/AC/OPET/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 23. With respect to this layered product, theneutralization degree after the retort processing and the oxygentransmission rate after the retort processing were measured. Theneutralization degree after the retort processing was 89 mol %, whilethe oxygen transmission rate after the retort processing was lower than0.2 cm³/m²·day·atm. Thus, with respect to the both, the layered productexhibited excellent values.

Example 26

Polyacrylic acid (PAA) with a number average molecular weight of 150,000was dissolved in distilled water. Thereafter, ammonia water was addedthereto and thereby 1.5 mol % of the carboxyl groups of the polyacrylicacid were neutralized. Thus, a polyacrylic acid aqueous solution wasobtained, in which the solid content concentration was 10 wt %.

Next, 60.8 parts by weight of tetramethoxysilane was dissolved in 83.6parts by weight of methanol. Subsequently, 22.9 parts by weight of3-chloropropyltrimethoxysilane was dissolved therein. Thereafter, 5.20parts by weight of distilled water and 12.9 parts by weight of 0.1Nhydrochloric acid were added thereto. Thus, a sol was prepared. This wasallowed to undergo hydrolysis and condensation reactions at 10° C. forone hour while being stirred. The sol thus obtained was diluted with 247parts by weight of distilled water, which then was added promptly to 567parts by weight of the above-mentioned 10-wt % polyacrylic acid aqueoussolution that were being stirred. Thus a solution (S26) was obtained.With respect to this solution (S26), the storage stability was evaluatedby the method described above.

Next, a layered product (26) that had a structure of gas barrier layer(2 μm)/AC/OPET (12 μm) was produced by the same method as in Example 23except that the solution (S26) was used instead of the solution (S23).The gas barrier layer of the layered product (26) was transparent andcolorless and had an excellent surface appearance.

Next, the layered product (26) was subjected to the ionization treatmentusing the calcium acetate aqueous solution (MI-1) under the sameconditions as those employed in Example 23. Subsequently, superfluouscalcium acetate was washed away with distilled water whose temperaturehad been adjusted to 80° C. Thereafter, it was dried at 80° C. for fiveminutes. Thus, a layered product (B-26) of the present invention wasobtained. With respect to the layered product (B-26), the neutralizationdegree of the carboxyl groups of the polyacrylic acid contained in thegas barrier layer was determined by the aforementioned method. As aresult, it was proved that 55 mol % of the carboxyl groups had beenneutralized by calcium ions. In addition, with respect to the layeredproduct (B-26), the oxygen barrier property, haze, and content ofinorganic components were evaluated by the aforementioned methods.

Furthermore, using the layered product (B-26), a layered product(B-26-1) that had a structure of gas barrierlayer/AC/OPET/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 23. With respect to this layered product, theneutralization degree after the retort processing and the oxygentransmission rate after the retort processing were measured. Theneutralization degree after the retort processing was 74 mol %, whilethe oxygen transmission rate after the retort processing was lower than0.2 cm³/m²·day·atm. Thus, with respect to the both, the layered productexhibited excellent values.

Example 27

Polyacrylic acid (PAA) with a number average molecular weight of 150,000was dissolved in distilled water. Thus, a polyacrylic acid aqueoussolution was obtained, in which the solid content concentration was 10wt %.

Next, 68.4 parts by weight of tetramethoxysilane was dissolved in 79.8parts by weight of methanol. Subsequently, 11.4 parts by weight of3-chloropropyltrimethoxysilane was dissolved therein. Thereafter, 5.13parts by weight of distilled water and 12.7 parts by weight of 0.1Nhydrochloric acid were added thereto. Thus, a sol was prepared. This wasallowed to undergo hydrolysis and condensation reactions at 10° C. forone hour while being stirred. The sol thus obtained was diluted with 189parts by weight of distilled water, which then was added promptly to 657parts by weight of the above-mentioned 10-wt % polyacrylic acid aqueoussolution that were being stirred. Thus a solution (S27) was obtained.With respect to this solution (S27), the storage stability was evaluatedby the method described above.

Next, a layered product (27) that had a structure of gas barrier layer(2 μm)/AC/OPET (12 μm) was produced by the same method as in Example 23except that the solution (S27) was used instead of the solution (S23).The gas barrier layer of the layered product (27) was transparent andcolorless and had an excellent surface appearance.

Next, the layered product (27) was subjected to the ionization treatmentusing the calcium acetate aqueous solution (MI-1) under the sameconditions as those employed in Example 23. Subsequently, superfluouscalcium acetate was washed away with distilled water whose temperaturehad been adjusted to 80° C. Thereafter, it was dried at 80° C. for fiveminutes. Thus, a layered product (B-27) of the present invention wasobtained. With respect to the layered product (B-27), the neutralizationdegree of the carboxyl groups of the polyacrylic acid contained in thegas barrier layer was determined by the aforementioned method. As aresult, it was proved that 69 mol % of the carboxyl groups had beenneutralized by calcium ions. In addition, with respect to the layeredproduct (B-27), the oxygen barrier property, haze, and content ofinorganic components were evaluated by the aforementioned methods.

Furthermore, using the layered product (B-27), a layered product(B-27-1) that had a structure of gas barrierlayer/AC/OPET/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 23. With respect to this layered product, theneutralization degree after the retort processing and the oxygentransmission rate after the retort processing were measured. Theneutralization degree after the retort processing was 91 mol %, whilethe oxygen transmission rate after the retort processing was lower than0.2 cm³/m²·day·atm. Thus, with respect to the both, the layered productexhibited excellent values.

Example 28

Polyacrylic acid (PAA) with a number average molecular weight of 150,000was dissolved in distilled water. Thus, a polyacrylic acid aqueoussolution was obtained, in which the solid content concentration was 10wt %.

Next, 68.4 parts by weight of tetramethoxysilane was dissolved in 79.7parts by weight of methanol. Subsequently, 11.3 parts by weight of3-mercaptopropyltrimethoxysilane was dissolved therein. Thereafter, 5.13parts by weight of distilled water and 12.7 parts by weight of 0.1Nhydrochloric acid were added thereto. Thus, a sol was prepared. This wasallowed to undergo hydrolysis and condensation reactions at 10° C. forone hour while being stirred. The sol thus obtained was diluted with 189parts by weight of distilled water, which then was added promptly to 658parts by weight of the above-mentioned 10-wt % polyacrylic acid aqueoussolution that were being stirred. Thus a solution (S28) was obtained.With respect to this solution (S28), the storage stability was evaluatedby the method described above.

Next, a layered product (28) that had a structure of gas barrier layer(2 μm)/AC/OPET (12 μm) was produced by the same method as in Example 23except that the solution (S28) was used instead of the solution (S23).The gas barrier layer of the layered product (28) was transparent andcolorless and had an excellent surface appearance.

Next, the layered product (28) was subjected to the ionization treatmentusing the calcium acetate aqueous solution (MI-1) under the sameconditions as those employed in Example 23. Subsequently, superfluouscalcium acetate was washed away with distilled water whose temperaturehad been adjusted to 80° C. Thereafter, it was dried at 80° C. for fiveminutes. Thus, a layered product (B-6) of the present invention wasobtained. With respect to the layered product (B-28), the neutralizationdegree of the carboxyl groups of the polyacrylic acid contained in thegas barrier layer was determined by the aforementioned method. As aresult, it was proved that 85 mol % of the carboxyl groups had beenneutralized by calcium ions. In addition, with respect to the layeredproduct (B-28), the oxygen barrier property, haze, and content ofinorganic components were evaluated by the aforementioned methods.

Furthermore, using the layered product (B-28), a layered product(B-28-1) that had a structure of gas barrierlayer/AC/OPET/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 23. With respect to this layered product, theneutralization degree after the retort processing and the oxygentransmission rate after the retort processing were measured. Theneutralization degree after the retort processing was 90 mol %, whilethe oxygen transmission rate after the retort processing was lower than0.2 cm³/m²·day·atm. Thus, with respect to the both, the layered productexhibited excellent values.

Example 29

Polyacrylic acid (PAA) with a number average molecular weight of 150,000was dissolved in distilled water. Thus, a polyacrylic acid aqueoussolution was obtained, in which the solid content concentration was 10wt %.

Next, 68.4 parts by weight of tetramethoxysilane was dissolved in 82.0parts by weight of methanol. Subsequently, 13.6 parts by weight ofgamma-glycidoxypropyltrimethoxysilane (manufactured by ChissoCorporation) was dissolved therein. Thereafter, 5.13 parts by weight ofdistilled water and 12.7 parts by weight of 0.1N hydrochloric acid wereadded thereto. Thus, a sol was prepared. This was allowed to undergohydrolysis and condensation reactions at 10° C. for one hour while beingstirred. The sol thus obtained was diluted with 185 parts by weight ofdistilled water, which then was added promptly to 634 parts by weight ofthe above-mentioned 10-wt % polyacrylic acid aqueous solution that werebeing stirred. Thus a solution (S29) was obtained. With respect to thissolution (S29), the storage stability was evaluated by the methoddescribed above.

Next, a layered product (29) that had a structure of gas barrier layer(2 μm)/AC/OPET (12 μm) was produced by the same method as in Example 23except that the solution (S29) was used instead of the solution (S23).The gas barrier layer of the layered product (29) was transparent andcolorless and had a good surface appearance.

Next, the layered product (29) was subjected to the ionization treatmentusing the calcium acetate aqueous solution (MI-1) under the sameconditions as those employed in Example 23. Subsequently, superfluouscalcium acetate was washed away with distilled water whose temperaturehad been adjusted to 80° C. Thereafter, it was dried at 80° C. for fiveminutes. Thus, a layered product (B-29) of the present invention wasobtained. With respect to the layered product (B-29), the neutralizationdegree of the carboxyl groups of the polyacrylic acid contained in thegas barrier layer was determined by the aforementioned method. As aresult, it was proved that 63 mol % of the carboxyl groups had beenneutralized by calcium ions. In addition, with respect to the layeredproduct (B-29), the oxygen barrier property, haze, and content ofinorganic components were evaluated by the aforementioned methods.

Furthermore, using the layered product (B-29), a layered product(B-29-1) that had a structure of gas barrierlayer/AC/OPET/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 23. With respect to this layered product, the dropped bagbreaking strength, neutralization degree after the retort processing,and oxygen transmission rate after the retort processing were measured.The neutralization degree after the retort processing was 92 mol %,while the oxygen transmission rate after the retort processing was lowerthan 0.2 cm³/m²·day·atm. Thus, with respect to the both, the layeredproduct exhibited excellent values.

Example 30

Polyacrylic acid (PAA) with a number average molecular weight of 150,000was dissolved in distilled water. Thereafter, ammonia water was addedthereto and thereby 1.5 mol % of the carboxyl groups of the polyacrylicacid were neutralized. Thus, a polyacrylic acid aqueous solution wasobtained, in which the solid content concentration was 10 wt %.

Next, 84.2 parts by weight of tetramethoxysilane (TMOS) was dissolved in90.8 parts by weight of methanol. Subsequently, 6.60 parts by weight of3-mercaptopropyltrimethoxysilane was dissolved therein. Thereafter, 5.93parts by weight of distilled water and 14.7 parts by weight of 0.1Nhydrochloric acid were added thereto. Thus, a sol was prepared. This wasallowed to undergo hydrolysis and condensation reactions at 10° C. forone hour while being stirred. The sol thus obtained was diluted with 173parts by weight of distilled water, which then was added promptly to 625parts by weight of the above-mentioned 10-wt % polyacrylic acid aqueoussolution that were being stirred. Thus a solution (S30) was obtained.With respect to this solution (S30), the storage stability was evaluatedby the method described above.

Next, a layered product (30) that had a structure of gas barrier layer(1 μm)/AC (0.1 μm)/OPET (12 μm)/AC (0.1 μm)/gas barrier layer (1 μm) wasproduced by the same method as in Example 14 except that a differentanchor coating agent was used in this example. The gas barrier layerswere transparent and colorless and had a good surface appearance. Theanchor coating agent used in Example 30 was a two-component anchorcoating agent in which a polyol base resin and an aliphatic isocyanatecuring agent were used. Takelac A626 (Trade Name) manufactured by MitsuiTakeda Chemicals, Inc. was used as the base resin, while Takenate A50(Trade Name) manufactured by Mitsui Takeda Chemicals, Inc. was used asthe curing agent. The base resin, the curing agent, and ethyl acetate(the moisture contained in ethyl acetate was 520 ppm) were mixedtogether in such a manner that the weight ratio between the base resinand the curing agent was 4/3 (the base resin/the curing agent).

Next, the layered product (30) was subjected to the ionization treatmentusing the calcium acetate aqueous solution (MI-1) under the sameconditions as those employed in Example 1. Subsequently, superfluouscalcium acetate was washed away with distilled water whose temperaturehad been adjusted to 80° C. Thereafter, it was dried at 80° C. for fiveminutes. Thus, a layered product (B-30) of the present invention wasobtained. With respect to the layered product (B-30), the neutralizationdegree of the carboxyl groups of the polyacrylic acid contained in thegas barrier layers was determined by the aforementioned method. As aresult, it was proved that 97 mol % of the carboxyl groups had beenneutralized by calcium ions. In addition, with respect to the layeredproduct (B-30), the oxygen barrier property, surface appearance, changein appearance through heating, tensile strength and elongation, haze,and content of inorganic components were evaluated by the aforementionedmethods.

Furthermore, using the layered product (B-30), a layered product(B-30-1) that had a structure of gas barrier layer/AC/OPET/AC/gasbarrier layer/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 1. With respect to this layered product, the dropped bagbreaking strength, peel strength, ionization degree after the retortprocessing, and the oxygen transmission rate after the retort processingwere measured. The ionization degree of the outermost layer after theretort processing was 98 mol %, while the oxygen transmission rate afterthe retort processing was lower than 0.2 cm³/m²·day·atm. Thus, withrespect to the both, the layered product exhibited excellent values.

Example 31

Polyacrylic acid (PAA) with a number average molecular weight of 150,000was dissolved in distilled water. Thereafter, ammonia water was addedthereto and thereby 1.5 mol % of the carboxyl groups of the polyacrylicacid were neutralized. Thus, a polyacrylic acid aqueous solution wasobtained, in which the solid content concentration was 10 wt %.

Next, 84.2 parts by weight of tetramethoxysilane (TMOS) was dissolved in91.1 parts by weight of methanol. Subsequently, 6.90 parts by weight ofgamma-isocyanatopropyltrimethoxysilane was dissolved therein.Thereafter, 5.93 parts by weight of distilled water and 14.7 parts byweight of 0.1N hydrochloric acid were added thereto. Thus, a sol wasprepared. This was allowed to undergo hydrolysis and condensationreactions at 10° C. for one hour while being stirred. The sol thusobtained was diluted with 176 parts by weight of distilled water, whichthen was added promptly to 622 parts by weight of the above-mentioned10-wt % polyacrylic acid aqueous solution that were being stirred. Thusa solution (S31) was obtained. With respect to this solution (S31), thestorage stability was evaluated by the method described above.

Next, a layered product (31) that had a structure of gas barrier layer(1 μm)/AC (0.1 μm)/OPET (12 μm)/AC (0.1 μm)/gas barrier layer (1 μm) wasproduced by the same method as in Example 14 except that a differentanchor coating agent was used in this example. The gas barrier layerswere transparent and colorless and had a good surface appearance. Theanchor coating agent used in Example 31 was a two-component anchorcoating agent in which a polyol base resin and an aliphatic isocyanatecuring agent were used. Takelac A626 (Trade Name) manufactured by MitsuiTakeda Chemicals, Inc. was used as the base resin, while Takenate A50(Trade Name) manufactured by Mitsui Takeda Chemicals, Inc. was used asthe curing agent. The base resin, the curing agent, and ethyl acetate(the moisture contained in ethyl acetate was 520 ppm) were mixedtogether in such a manner that the weight ratio between the base resinand the curing agent was 4/3 (the base resin/the curing agent).

Next, the layered product (31) was subjected to the ionization treatmentusing the calcium acetate aqueous solution (MI-1) under the sameconditions as those employed in Example 1. Subsequently, superfluouscalcium acetate was washed away with distilled water whose temperaturehad been adjusted to 80° C. Thereafter, it was dried at 80° C. for fiveminutes. Thus, a layered product (B-31) of the present invention wasobtained. With respect to the layered product (B-31), the neutralizationdegree of the carboxyl groups of the polyacrylic acid contained in thegas barrier layers was determined by the aforementioned method. As aresult, it was proved that 82 mol % of the carboxyl groups had beenneutralized by calcium ions. In addition, with respect to the layeredproduct (B-31), the oxygen barrier property, surface appearance, changein appearance through heating, tensile strength and elongation, haze,and content of inorganic components were evaluated by the aforementionedmethods.

Furthermore, using the layered product (B-31), a layered product(B-30-1) that had a structure of gas barrier layer/AC/OPET/AC/gasbarrier layer/adhesive/ONy/adhesive/PP was produced by the same methodas in Example 1. With respect to this layered product, the dropped bagbreaking strength, peel strength, ionization degree after the retortprocessing, and oxygen transmission rate after the retort processingwere measured. The ionization degree of the outermost layer after theretort processing was 97 mol %, while the oxygen transmission rate afterthe retort processing was lower than 0.2 cm³/m²·day·atm. Thus, withrespect to the both, the layered product exhibited excellent values.

Tables 5 and 6 indicate the production conditions and evaluation resultsof the examples described above.

TABLE 5 Univalent Compound Carboxylic Content of Ion (A·A′) Acid-Inorganic Added Added Polyvalent Ion Containing Contents Ion AmountCompound (B) Amount Ion Neutralization Examples Polymer [wt %] Type [mol%] Type Type [mol % (*)] Type Degree Example 23 PAA 30 NH₄ ⁺ 1.5 TMOSa-1 10 Ca²⁺ 69 Example 24 PAA 30 NH₄ ⁺ 1.5 TMOS a-2 10 Ca²⁺ 86 Example25 PAA 30 NH₄ ⁺ 1.5 TMOS a-3 10 Ca²⁺ 50 Example 26 PAA 30 NH₄ ⁺ 1.5 TMOSa-1 20 Ca²⁺ 55 Example 27 PAA 30 — — TMOS a-1 10 Ca²⁺ 69 Example 28 PAA30 — — TMOS a-2 10 Ca²⁺ 85 Example 29 PAA 30 — — TMOS b-1 10 Ca²⁺ 63Example 30 PAA 35 NH₄ ⁺ 1.5 TMOS a-2 5 Ca²⁺ 97 Example 31 PAA 35 NH₄ ⁺1.5 TMOS b-2 5 Ca²⁺ 82 a-1: 3-chloropropyltrimethoxysilane a-2:3-mercaptopropyltrimethoxysilane a-3:N-(3-triethoxysilylpropyl)gluconamide b-1:gamma-glycidoxypropyltrimethoxysilane b-2:gamma-isocyanatopropyltrimethoxysilane (*) The ratio of Compound (A orA′) to the total of Compound (A or A′) and Compound (B) [(Compound (A orA′))/(Compound (A or A′) + Compound (B))]

TABLE 6 Oxygen Transmission Rate (cm³/m² · day · atm) Stability of HazeBefore Retort After Retort Examples Solution (S) (%) ProcessingProcessing Example 23 4 days 1.5 0.2 0.2> Example 24 4 days 1.8 0.3 0.2>Example 25 4 days 2.0 0.5 0.2> Example 26 4 days 1.2 0.5 0.2> Example 27At least 7 days 2.0 0.2 0.2> Example 28 At least 7 days 2.4 0.3 0.2>Example 29 At least 7 days 4.8 0.2 0.2> Example 30 4 days 2.2 0.2 0.2>Example 31 4 days 4.7 0.2 0.2>

As shown in Table 6, the layered products (B-23) to (B-31) of Examples23 to 31 each exhibited a high oxygen barrier property even under highhumidity conditions. The layered products (B-23) to (B28) and (B-30)each had a smaller haze value, which was 3% or less. Accordingly, theywere transparent and had a good surface appearance.

Furthermore, as shown in Table 6, the layered products (B-23-1) to(B-31-1) of Examples 23 to 31 each had a high oxygen barrier propertyeven after the retort processing.

Moreover, as shown in Table 6, the solutions (S23) to (S29) each did notgelate even after 2 days and also had an excellent coating property.

In the above, the embodiments of the present invention were describedusing examples. The present invention, however, is not limited to theabove-mentioned embodiments but can be applied to other embodimentsaccording to the technical idea of the present invention.

INDUSTRIAL APPLICABILITY

The present invention is applicable to layered products that arerequired to have a gas barrier property and methods for producing them.Particularly, the gas barrier layered product of the present inventionexhibits a high oxygen barrier property irrespective of humidity. Italso exhibits a high oxygen barrier property even after being subjectedto the retort processing. Accordingly, the gas barrier layered productof the present invention is used effectively as packaging materials forfood, medicine, medical equipment, machine parts, garments, etc. It isused particularly effectively for a food packaging use where the gasbarrier property is required under a high humidity condition.

1. A gas barrier layered product comprising a base material and a layerstacked on at least one surface of the base material, wherein the layeris formed of a composition comprising: a hydrolyzed and condensedproduct of at least one compound (L) comprising a metal atom to which atleast one characteristic group selected from a halogen atom and analkoxy group has been bonded; and a neutralized product of a polymercomprising at least one functional group selected from a carboxyl groupand a carboxylic anhydride group, wherein at least 55 mol % of a —COO—group contained in the at least one functional group has beenneutralized with a metal ion having a valence of two or more, whereinthe compound (L) comprises at least one compound (A) represented by thefollowing chemical formula (I) and at least one compound (B) representedby the following chemical formula (II):M¹(OR¹)_(n)X¹ _(k)Z¹ _(m-n-k)  (I) wherein M¹ is Si, Al, Ti, Zr, Cu, Ca,Sr, Ba, Zn, B, Ga, Y, Ge, Pb, P, Sb, V, Ta, W, La, or Nd; R¹ is an alkylgroup; X¹ is a halogen atom; Z¹ is an alkyl group substituted by afunctional group having reactivity to a carboxyl group; m is equal to avalence of M¹; n is an integer of 0 to (m−1); k is an integer of 0 to(m−1); and 1≦n+k≦(m−1),M²(OR²)_(q)R³ _(p-q-r)X² _(r)  (II) wherein M² is Si, Al, Ti, Zr, Cu,Ca, Sr, Ba, Zn, B, Ga, Y, Ge, Pb, P, Sb, V, Ta, W, La, or Nd; R² is analkyl group; R³ is an alkyl group, an aralkyl group, an aryl group, oran alkenyl group; X² is a halogen atom; p is equal to a valence of M²; qis an integer of 0 to p; r is an integer of 0 to p; and 1 ≦q+r≦p, andwherein a mole ratio of the compound (A)/the compound (B) is in a rangeof 0.5/99.5 to 40/60.
 2. The gas barrier layered product according toclaim 1, wherein in the chemical formula (I), the functional grouphaving reactivity to a carboxyl group is at least one selected from thegroup consisting of an epoxy group, an amino group, a hydroxyl group, ahalogen atom, a mercapto group, an isocyanate group, a ureide group, anoxazoline group, and a carbodiimide group.
 3. The gas barrier layeredproduct according to claim 2, wherein in the chemical formula (I), thefunctional group having reactivity to a carboxyl group is at least oneselected from the group consisting of an epoxy group, an amino group,and an isocyanate group.
 4. The gas barrier layered product according toclaim 1, wherein in the chemical formula (I), M¹ is Si, Al, Ti, or Zr;and wherein in the chemical formula (II), M² is Si, Al, Ti, or Zr. 5.The gas barrier layered product according to claim 1, wherein thecompound (A) is at least one compound selected from the group consistingof gamma-glycidoxypropyltrimethoxysilane,gamma-glycidoxypropyltriethoxysilane,gamma-glycidoxypropyltrichlorosilane, gamma-aminopropyltrimethoxysilane,gamma-aminopropyltriethoxysilane, gamma-aminopropyltrichlorosilane,gamma-chloropropyltrimethoxysilane, gamma-chloropropyltriethoxysilane,gamma-chloropropyltrichlorosilane, gamma-bromopropyltrimethoxysilane,gamma-bromopropyltriethoxysilane, gamma-bromopropyltrichlorosilane,gamma-mercaptopropyltrimethoxysilane,gamma-mercaptopropyltriethoxysilane,gamma-mercaptopropyltrichlorosilane,gamma-isocyanatopropyltrimethoxysilane,gamma-isocyanatopropyltriethoxysilane,gamma-isocyanatopropyltrichlorosilane,gamma-ureidopropyltrimethoxysilane, gamma-ureidopropyltriethoxysilane,and gamma-ureidopropyltrichlorosilane.
 6. The gas barrier layeredproduct according to claim 1, wherein the gas barrier layered producthas an oxygen transmission rate of 1.0 cm³/m²·day·atm or lower in anatmosphere of 20° C. and 85% RH.
 7. The gas barrier layered productaccording to claim 1, wherein the content of an inorganic componentcontained in the composition is 5 to 50 wt %.
 8. The gas barrier layeredproduct according to claim 1, wherein the polymer is at least onepolymer selected from polyacrylic acid and polymethacrylic acid.
 9. Thegas barrier layered product according to claim 1, wherein the metal ionis at least one selected from the group consisting of a calcium ion, amagnesium ion, a barium ion, and a zinc ion.
 10. The gas barrier layeredproduct according to claim 1, wherein the composition further comprisespolyalcohols.
 11. The gas barrier layered product according to claim 10,wherein a weight ratio of the neutralized product/the polyalcohols is10/90 to 99.5/0.5.
 12. The gas barrier layered product according toclaim 1, further comprising an adhesive layer disposed between the basematerial and the layer.
 13. The gas barrier layered product according toclaim 1, wherein the base material comprises a paper layer.
 14. The gasbarrier layered product according to claim 1, wherein a mole ratio ofthe compound (A)/the compound (B) is in a range of 3/97 to 40/60. 15.The gas barrier layered product according to claim 1, wherein the layerhas a sea-island structure containing a sea phase (P) and an islandphase (Q).
 16. The gas barrier layered product according to claim 15,wherein the sea phase (P) has a sea-island structure composed of: a seaphase (P1) predominantly comprising the neutralized product of thepolymer; and an island phase (P2) predominantly comprising thehydrolyzed and condensed product of the compound (L), and the islandphase (Q) has a sea-island structure composed of: a sea phase (Q1)predominantly comprising the neutralized product of the polymer; and anisland phase (Q2) predominantly comprising the hydrolyzed and condensedproduct of the compound (L).
 17. A packaging medium comprising a gasbarrier layered product according to claim
 1. 18. The packaging mediumaccording to claim 17, wherein a base material included in the gasbarrier layered product comprises a paper layer.
 19. A method forproducing a gas barrier layered product, comprising: a first process offorming, on a base material, a layer composed of a compositioncomprising: a hydrolyzed and condensed product of at least one compound(L) comprising a metal atom to which at least one characteristic groupselected from a halogen atom and an alkoxy group has been bonded; and apolymer comprising at least one functional group selected from acarboxyl group and a carboxylic anhydride group; and a second process ofbringing the layer into contact with a solution comprising a metal ionwith a valence of two or more, wherein at least 55 mol % of a —COO—group contained in the at least one functional group is neutralized withthe metal ion having a valence of two or more, wherein the compound (L)comprises at least one compound (A) represented by the followingchemical formula (I) and at least one compound (B) represented by thefollowing chemical formula (II):M¹(OR¹)_(n)X¹ _(k)Z¹ _(m-n-k)  (I) wherein M¹ is Si, Al, Ti, Zr, Cu, Ca,Sr, Ba, Zn, B, Ga, Y, Ge, Pb, P, Sb, V, Ta, W, La, or Nd; R¹ is an alkylgroup; X¹ is a halogen atom; Z¹ is an alkyl group substituted by afunctional group having reactivity to a carboxyl group; m is equal to avalence of M¹; n is an integer of 0 to (m−1); k is an integer of 0 to(m−1); and 1≦n+k≦(m−1),M²(OR²)_(q)R³ _(p-q-r)X² _(r)  (II) wherein M² is Si, Al, Ti, Zr, Cu,Ca, Sr, Ba, Zn, B, Ga, Y, Ge, Pb, P, Sb, V, Ta, W, La, or Nd; R² is analkyl group; R³ is an alkyl group, an aralkyl group, an aryl group, oran alkenyl group; X² is a halogen atom; p is equal to a valence of M²; qis an integer of 0 to p; r is an integer of 0 to p; and 1 ≦q+r≦p, andwherein a mole ratio of the compound (A)/the compound (B) is in a rangeof 0.5/99.5 to 40/60.
 20. The production method according to claim 19,further comprising: a process of preparing a solution (S) comprising thepolymer and at least one compound comprising a metallic element selectedfrom the group consisting of the compound (L), a partial hydrolysate ofthe compound (L), a total hydrolysate of the compound (L), a partialhydrolyzed and condensed product of the compound (L), and a productobtained through condensation of a part of a total hydrolysate of thecompound (L); and a process of forming the layer by applying thesolution (S) to the base material and then drying it.
 21. The productionmethod according to claim 19, wherein the first process comprises: aprocess of forming the hydrolyzed and condensed product of the compound(L); a process of preparing a solution (S) comprising the polymer andthe hydrolyzed and condensed product of the compound (L); and a processof forming the layer by applying the solution (S) to the base materialand then drying it.
 22. The production method according to claim 20,wherein in the polymer contained in the solution (S), 0.1 to 10 mol % ofa —COO— group contained in the at least one functional group has beenneutralized with a univalent ion.
 23. The production method according toclaim 19, further comprising a process of heat-treating the layer at atemperature of 120 to 240° C., after the first process and before and/orafter the second process.
 24. The production method according to claim19, wherein a mole ratio of the compound (A)/the compound (B) is in arange of 3/97 to 40/60.